Which phylum to not have an internal or external skeleton or shell?

How did alexander fleming’s research solve a societal problem? he developed ways to treat inherited diseases. he advocated for regular hand washing to kill germs. he discovered a new type of medicine that could treat infections. he discovered the cause of mad cow disease, an emerging disease.

Why has two different alleles for the same trait?

Methane gas created by a cows flatulence especially in a large herd is a greenhouse gas. true or false.