When using terms such as coelomates and pseudocoelomates, a “grade” is

Which statement best describes a keystone species? o a. it has littlelmenetic variation. it has an extremely high population. 0 b. 0 c. it remains unaffected by all environmental changes. od. it has a strong influence on the ecosystem. 0 e. it's the first species to populate a new ecosystem.

Why is it important to reduce the number of chromosomes in half when forming gametes for sexual reproduction?

Describe how a non-resistant staphylococcus aureus bacterium can produce a bacterium that is resistant to methicillin