Scientists believe that at the end of the Mesozoic Era, a large comet struck Earth. What was one major impact of the comet strike?

Which of these is the most likely consequence of falling petroleum price

How many trophic levels are there in the following food chain? phytoplankton - shrimp - perch - pike - osprey

Dna. we have heard that we are a product of our dna. but where is it? how do we "get" our dna? it is passed to us, from our parents, but in what form? several vocabulary words associated with inheritance are used interchangeably and sometimes, incorrectly. let's see if you can clear this up for someone just learning about inheritance and cell structure.