5 major headlines to start the week

President Trump says he's not worried about his son's entanglement in the Russia probe.

A 20-year-old Iowa student has been missing for nearly three weeks.

The Venezuelan president says "far right" opponents tried to kill him with explosive drones.

Countdown to zero? See how Pakistan is trying to wipe out polio.

And while it may take humans centuries to adapt to rising temperatures, sharks have already started along American coasts.

Before you begin your week, have a look back at some of the top stories of the weekend.

Trump says it's a 'complete fabrication' he's concerned his son is in legal trouble in Russia probe

The president says it's a "complete fabrication" that he's concerned about Donald Trump Jr.'s 2016 meeting with Russians at Trump Tower.

The disappearance of University of Iowa student Mollie Tibbetts: A timeline

The desperate search continues for Mollie Tibbetts, who vanished from Brooklyn, Iowa, on July 16.

Explosive drones detonate in 'assassination attempt' on Venezuelan president

Venezuelan President Nicolas Maduro says the drones that exploded near him at a military event Saturday were part of an attempt to assassinate him.

Inside Pakistan's fight for zero polio cases, where women are on the frontlines

Pakistan has undertaken anti-polio campaigns that have brought the number of new cases in the country close to zero.

Sharks are changing where they swim, breed and hunt along American coasts, say experts

Sharks are adapting to an ever-hotter planet by changing when and where they swim, breed and hunt, and that could force other species to adapt, too.
Related topics:
abc newsnational
Copyright © 2019 ABC News Internet Ventures.