What are masterpieces and why are there so few of them?

Explain why phospholipid molecules form a bilayer. (3 marks)

The following hormone had their receptors in the cell membrane except a-insulin b-tsh c-gh d- cortisol

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important