Momentum before key contests in his republican rivals home state. A new poll here in texas shows ted cruz ahead, and john kasich has been leading in ohio. But another poll put marco rubio well behind trump in his home state of florida. Today, trump focused on a different republican candidate, one from four years ago. The feud between mitt romney and donald trump started yesterday when romney repeated his call for trump to release his tax returns. Trump then took to twitter to call romney one of the worst g. O. P. Candidates ever and a dope. Trump also tweeted a picture of himself signing what he said was a recent tax return. The caption, isnt this ridiculous . The tax issue bedeviled romney in the 2012 campaign after Democratic Senate leader harry reid made a similar claim to what romney is now saying about trump. The words out that he hasnt paid any taxes for 10 years. Let him prove that he has paid taxes, because he hasnt. Was later debunked. For his part, trump has boasted he tries to keep his tax bill low. I fight like hell not to pay taxes. I hate the way the government spends my money. Reporter and he noted on twitter that, tax returns have zero to do with someones net worth. Romneys response, me thinks the conald doth protest too much. Trumps g. O. P. Rivals marco rubio and ted cruz have both pledged to release their returns. Theyre not very exotic, but we will release them. I havent made enough money that my tax returns are interesting. Reporter donald trump is on a threestate winning street and won 60 of the delegates awarded so far. Tuesday presents the biggest haul of all 595 delegates, just under half of the amount required to secure the republican nomination. Pelley the next democratic debate i should say primary, we could just turn this into a revival. Reporter Hillary Clintons inner preacher came out today as carolina low country. I think we need more singing, dont you . I sing because im happy. I sing because im free reporter in michigan, Bernie Sanders was focused on minorities, too, meeting with residents in waterstricken flint. People were coming saying, this, water is brown. Were getting rashes, and they continued to ignore it. Reporter neither candidate can win in the delegaterich super tuesday states without minority support. In 2008, African Americans alone made up half of the democratic electorate in alabama and georgia, and nearly a third in virginia and tennessee. 32 of democratic voters in texas were hispanic. When you have people like trump saying that mexicans are outrage. Reporter a new National Poll finds clinton leading a margin of two to one. She has a similar wedge African Americans though her husbands crime bill has been a Sticking Point for some. Two black lives matters protesters interrupted a clinton fundraiser in charlestown last night. Well, can i talk . And maybe you can listen to what i say. Reporter the protesters were escorted out, and clinton later said she was sorry for some of the terms she used in the 90s, including the use of the phrase super predators. She was using the term to describe violent young gang members, but now, 20 years later, says it was a poor choice of words. Both clinton and sanders want to reform the way drug crimes, in particular, are handled, scott, because they say too many young blacks and latinos are ending up behind bars. Pelley this evening, president obama claimed progress against the isis terrorist group in syria. He said that isis has lost 40 its troops, and is reduced to using civilians as human shields. But the wider war in syria is not going mr. Obamas way. Americanbacked rebels are on the run. The forces of the assad dictatorship are advancing for the first time in years because of russian air support and iranian troops. It is rare fair reporter to get into syria, but our Elizabeth Palmer covered the dictators advance today through an apocalyptic land. Reporter this used to be a neighborhood. Now its a battlefield. Where the syrian army says its got the enemy on the run. Theres just been an air strike behind me. Were about five miles from the center of damascus, and the syrian army is trying to clear this suburb of opposition fighters. There is certainly no ceasefire soon. Solmer, one of the syrian soldiers, takes take us to see the buildings half a mile away where he says the rebels are now hiding. Overhead, we can hear the helicopters scouting their target. Then. explosion what are they hitting, solmer . Theyre terrorists, he says. Those are barrel bombs . Barrel broms basically canisters filled with explosives rolled out of a chopper. Theyre cheap but horribly inaccurate. And are there any civilians left over there . No, no, he says only fighters, but there are fighters families, too, cowering under the attacks. Nearby, we enter tunnels the soldiers say were dug by fighters with the Al Qaedalinked alnusra front where they hit hid and fought for years. Charge, leads the way through ruins he now controls. Youre still using air strike nghtz suburbs in order to fight nusra . Yes, he says, because theyre dangerous for syria and the world so were justified in use anything weapons that are legal. But that means that when this overstretched and undertrained army does gain ground, its victories look like nothing marine few blocks of rubble. But the truth is, scott, that by now, all sides in this war are completely exhausted, and unlikely as it sounds, just a couple of suburbs over, the army has actually reached a mini truce with the rebels to allow food and supplies to reach civilians. Pelley Elizabeth Palmer with rare firsthand reporting inside syria tonight. Elizabeth, thank you. Today, the director of the f. B. I. Said that his battle with apple is the toughest fight hes faced in government. A federal magistrate ordered one of the San Bernardino terrorists, but today, apple told the court that order is dangerous. Jeff pegues has more. Reporter in its filing, apple says the f. B. I. Is seek a dangerous power and that it would be forced to dedicate six to 10 apple engineers to create new code that apple callses the government operating system or government o. S. Apple said there would even have to be a Government Forensic Lab on Company Ground that could be used to open hundreds of other seized diswies dwooises in law law enforcements possession. Apple says the Company Believes the case triggers First Amendment protections, and writing computer code is equivalent to free speech. This is the hardest question i have seen in government. Reporter f. B. I. Director james comey reassured members of Congress Today that the bureau iphone used by San Bernardino terrorist syed farook. Comey said the f. B. I. Is stand on firm legal ground, but Congress Needs to set the limits on how far government investigators can go. Im a huge fan of privacy. I love encryption. Its a great thing. But our need for Public Safety and our need for privacy are crashing into each other, and weve got to sort that out as a people. Reporter apple agrees that congress should have a bigger role in this debate, but, scott, the court case is moving forward. Google and facebook are expected to file legal papers in support of apple. Pelley jeff pegues for us tonight. Jeff, thank you. Tornadoes in several states yesterday killed at least four people, including three in waverly, virginia, where we find chip reid tonight. Man. Reporter Vincent Donald was about to sit down right here to watch tv when the tornado sheering off the roof and the wall. Do you feel lucky to be alive . Im not lucky. Im blessed. Reporter but the tornado tore his neighbors mobile home from its foundation and sent it sailing across a highway. A twoyearold boy, his father, and another man died. Their bodies and were dewe were found 300 yards away. Somehow, the boys mother survived with serious injuries. In nearby appomattox, virginia, a 78yearold man died and 100 buildings were damaged after a funnel cloud left an eightmile path of destruction. At least three tornadoes were reported in north carolina. In ox fard, parts of this farm were leveled. In pennsylvania, a tornado ripped through amish country, hitting structures in narvon. A torrential downpour lead to flash flooding in and around washington, d. C. In the new york area, a gust of wind sent this truck airborne. Off queens, new york, 12foot waves capsized a Coast Guard Boat as it was trying to rescue fishermen on another vessel that had run aground. And back here in waverly, virginia, youre looking at a photograph of aplus tires before the tornado. Now youre look at aplus tires after the tornado. This was theiage door. That up there is the metal that was once the roof. Scott, its a good example of what happens when a tornado meets a Building Made of sheet metal. Pelley and we want to point out, no one was injured in the coast guard incident today. Chip, thanks very much. The worlds appetite for portable electronics has triggered huge demand for rechargeable batters, but many of these batteries are now bursting into flames in places you would least expect. Vinita nair is looking into this. Reporter when the fire first ignited, employee as this kentucky gas station thought it was a bomb. It turned out to be an ecigarette that exploded in he suffered third degree burns. Its just the latest incident involving defective lithium ion batteries that power ecigarettes. 21yearold Evan Spahlinger had to be placed in a medically induced coma for three days after one of them blew up in his mouth. Its an alternative to smoking cigarettes. Its supposed to be a safer and a healthier way of doing it. Reporter the same battery cells that power ecigarettes, also power hoverboards. Since december there have been 52 reported incidents involving hoverboards catching on fire. Jay whitacre is a professor at Carnegie Mellon university. He said the demand to make these products cheaper and more powerful has led some companies to cut cornerrers. What were seeing right now is a situation where may be of these batteries are simply not made to the same standard as the battery that are made say, at sony or panasonic, which have much more stringent quality control. Lithionionpowered items are considered highpower applications. If their batteries are badly designed when they are charged they can overheat. Is it something that the user is doing incorrectly. No. In general, with this kind of technology, its very difficult for the user to be at fault. There is a wellcontrolled charging circuit, and there should be a good package that the cell lives in. Both of those things should be designed to protect the user. Reporter industry advocates say these incidents are still rare and that users should always use compatible batteries and chargers. They say to avoid battery contact with metal objects, scott, such as coins, keys, or jewelry. Pelley vinita nair, thank you very much. Theres a plan to give wider air passengerrers wider seats. Well get to the bottom of it. And a young fan bags quite a even news continues. Go, go, go, go, go, go. Touchdown choir and harp music. This place, its the bestkept secret in football since. Hey, how did he get in here . and with toe nail fungus fight it with jublia. Jublia is a prescription medicine used to treat toenail fungus. Use jublia as instructed by your doctor. Now thats prime time. Most common side effects include ingrown toenail, application site redness, itching, swelling, burning or stinging, blisters, and pain. You ready to fight it . Ask your doctor if jublia is right for you. Yknow, i look great in purple. Pet moments are beautiful, unless you have allergies. Then your eyes may see it differently. Only flonase is approved to relieve both itchy, watery eyes and congestion. No other nasal allergy spray can say that. When we breathe in allergens our bodies react by over producing six key inflammatory substances that cause our symptoms. Most allergy pills only control one substance. Flonase controls six. And six is greater than one. Let your eyes decide. Flonase. 61 changes everything. My tempurpedic cuddles better than my husband does. But thats just between you and me. Its really cool to the touch. At mattress firm,get zero percent apr financing. Visit mattress firm, americas number one tempurpedic retailer today. Theres only one egg that gives you better taste and better nutrition in so many varieties. Classic. Cage free. And organic. Only egglands best. Better taste. Better nutrition. Better eggs. What backache . What sore wrist . What headache . Advil makes pain a distant memory. Nothing works faster stronger or longer what pain . Advil. That could revolutionize the inflight experience. Think flying station wagon. Heres kris van cleave. Reporter jet maker airbus wants to patent a seating concept taking a row of three Airline Seats and turning it into a rapidly and easily reconfigerable bench. It could seat the traditional three passengers, shift to two people who need dcialg space, including overweight passengers, or even fit a fourth person, like two parents and two small children. The airlines will consider anything that allows them to make a buck. Reporter Ben Mutzabaugh is the editor of usa todays today in the sky blog. If weve seen nothing else in the airline industry, theyre very clever about coming up with ways to sell seats to passengers, especially when they can charge more for either seats that are better or for seats that are less awful. Reporter airbus previously sought patents for a design stacking passengers and this semistanding concept. Hexagon pattern where the middle seat faces the passengers in the eye and window. Tennessee congressman Stephen Cohen worries extra seats could jeopardizize safety making it hard to evacuate in the required 90 seconds as seen in this video. Hes author add a bill requiring the f. A. A. To set minimum seatsize standards. If people cant get out of an airplane in emergency conditions they lose their lives. It shouldnt be afternoon an accident. After an accident, its too late and people are dead. Reporter the big question now, scott, will an airline say they want these seats and will safety regulators ever allow them to be installed in a plane . Pelley kris van cleave, thank you, chris. N. B. A. . What a new study has found next. Stock prices, earnings, and dividends. An equity summary score that consolidates and 7. 95 online u. S. Equity trades, lower than td ameritrade, schwab, and etrade, you realize the smartest investing idea isnt just what you invest in, but who you invest with. Song thats life song thats life song thats life song thats life thats life. You diet. You exercise. And if you still need help lowering your blood sugar. This is jardiance. Along with diet and exercise, jardiance works around the clock to lower blood sugar in adults with type 2 diabetes. It works by helping your body to get rid of some of the sugar it doesnt need through urination. This can help you lower blood sugar and a1c. Or lowering systolic blood pressure, jardiance could help with both. 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Theres no deep couch sitting. Definitely not good for my back. This is the part i really dont like right here. doorbell whats that . A package its a swiffer wetjet. It almost feels like its moving itself. This is kind of fun. That comes from my floor . Eww this is deep couch sitting. [jerry bell iii] deep couch sitting pelley heart problems account for threequarters of sportsrelated deaths in young athletes. Lives, and heres dr. Jon lapook. Reporter two years ago Isaiah Austin was one of the nations Top College Basketball players. Then, a physical before the n. B. A. Draft revealed a heart problem, ending his career. I just didnt know what to do with it, but it was just you know, just accepting it, accepting that life is in and health is more important than a game. Reporter in the u. S. , sportsrelated sudden cardiac death is highest among basketball players. One big question is whats a normal heart size for these athletes . To find out, dr. Aaron lanedavies and colleagues reviewed the heart ultrasounds of more than 500 n. B. A. Players. When you first saw them, you thought these are big hearts. These are abnormal . The first instinct is to say these hearts are enlongranged. Were not used to seeing hearts for people that are this big. The average n. B. A. Player is 67 and the average weight is 222 pounds. Reporter it turns out, gets bigger with exercise, although the hearts of the n. B. A. Players were about 10 thicker than normal, that was not felt to be dangerous. The research establishaise baseline for doctors going forward. And how does this help us . This should help us distinguish those changes from dangerous heart conditions that can lead to sudden cardiac death. Reporter in addition, they found that the aorta, the major artery leaving the heart, is also bigger in these athletes and knowing that will help with future diagnosis. Scott, dr. Engel says this is now a model for evaluating athletes in other sports. Pelley jon lapook, thank you very much, jon. Well, soccers biggest star came through with heart today for his biggest fan. Fan. A fiveyearold was photographed wearing a lionel messi shirt made from a plastic bag. It went online and messi sent him an autographed shirt from argentinas national team. Up next, a math teachers formula for success against the odds. So lets Start Talking about your long term goals. Knowing your future is about more than just you. Its how edward jones makes sense of investing. For adults with an advanced lung cancer called squamous nonsmall cell, previously treated with platinumbased chemotherapy, its not every day something this big comes along. A chance to live longer with. Opdivo, nivolumab. Opdivo is the first and only immunotherapy fda approved based on a Clinical Trial demonstrating longer life. For these patients. In fact, opdivo significantly increased the chance of living longer versus chemotherapy. Opdivo is different. It works with your immune system. Opdivo can cause your immune system to attack and affect how they work. This may happen any time during or after treatment has ended, and may become serious and lead to death. See your doctor right away if you experience new or worsening cough; chest pain; shortness of breath; diarrhea; severe stomach pain or tenderness; severe nausea or vomiting; extreme fatigue; constipation; excessive thirst or urine; swollen ankles; loss of appetite; rash; itching; headache; confusion; hallucinations; muscle or joint pain, or flushing as this may keep these problems from becoming more serious. These are not all the possible side effects of opdivo. Tell your doctor about all your medical conditions, including immune system problems, or if youve had an organ transplant, or lung, breathing, or liver problems. A chance to live longer. Ask your doctor if opdivo is right for you. Bristolmyers squibb thanks the patients and physicians who participated in the opdivo Clinical Trial. I take pictures of sunrises. Its my job and its also my passion. But with my back pain i couldnt sleep. Then i found aleve pm. Aleve pm is theonly one to combine a safe sleep aidplus the 12hour pain relievingstrength of aleve. And now. Im back. Pelley we end tonight with a solution to a math problem that has stumped the best minds for centuries. How do you get school kids to succeed at calculus . Heres mireya villarreal. Reporter from the outside, Lincoln High School does not look like a place that inspires greatness. Old, with gates on the windows, in a tough east l. A. Neighborhood. Today is all about making your life easier. Reporter but look beyond all of that, and youll find this man, anthony yom. This is almost similar to this guy right here, right . Reporter the son of korean immigrants, yom teaches what is considered the hardest class in school, advanced placement calculus. To make sure to provide that environment where kids are not shamed of asking questions. Do you get it . Reporter his approach to teaching goes beyond calculating the slope of a curve. Yom makes his class meet after schools, on weekends, and even holidays. The hard work has paid off. Its not always fun, but i do know for sure, once they get the score and if i ask them, hey, was it worth it . Every single one of them say it was so worth it. Reporter for three years in a row, every student that has walked into his class has passed the a. P. Calculus test. And this year, one student, Cedrick Argueta, got every question right. His style of teaching commands respect and his personality is very likable. He gets ton his students on a personal level. Reporter what is the secret here . They know that i sincerely care about them, and its prep for them. Reporter with love . Yeah, with love. Reporter Cedrick Argueta and yom were both ordered by the l. A. School board and president the white house science fair. The 17yearold wants to go to caltech and become a rocket scientist, while yoms focus is on his next batch of calculus students. This is not rocket science. Reporter mireya villarreal, cbs news, los angeles. Pelley and thats the cbs evening news for tonight. For all of us at cbs news all around the world, good night. Captioning sponsored by cbs access. Wgbh. Org from Sony Pictures studios, its americas game. Wheel. Of. Fortune ladies and gentlemen, here are the stars of our show, pat sajak and vanna white. Well, there we are. Thank you, jim. Thanks, everybody. There it is. Right there. Thank you. Appreciate that. See you later. Wow yeah, i know. Hi, gang. Get ready. Your moment in the sun has arrived. 1,000 for this first puzzle. Its a phrase our first toss up. Here we go. [ bell chimes ] jessica. No sales tax. Yeah, thats it. Nothing to it. [ chuckles ] jessica nadeau, right. Yes. Is from fair haven, vermont. What do you do back there . I am the director of a community and employment support program. We support folks with barriers to employment to achieve their goals and dreams. Youre married. Yes, i am, to my very patient and tolerant husband, rob. We have three kids olesia, olivia, and ethan. And they love moms cupcakes. They absolutely do. [ chuckles ]