Can someone please help me with these three problems ASAP .. I have to get it done right now

What is thought to have caused the mass extinction at the end of the cretaceous period?

Modern whales developed their traits through natural selection what occurs during the process of natural selection

The idea that all living things are made up of cells is considered scientific law. this means the idea is an emerging scientific idea that has a logical explanation. has been tested with similar results at least twice. is supported by scientific consensus and a large amount of evidence. has been rejected only once by the scientific community