Explain the 10% rule for energy flow

People who exercise for an hour may have lower cholesterol levels. is that a statement? a law? or a hypothesis?

Which best describes a rhinovirus? o a. a virus that causes a common cold o b. a protective shell around a virus o c. a tube the comes off a virus o d. a piece of dna transferred by a virus

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