Special mating plumage produced by birds during a time of year is an example of:

a reproductive isolating mechanism
winter coloration to blend into the background
as aspect of aging of the birds as they become old and senile
none of these

lysosomes contain a variety of enzymes, enabling the cell to break down various biomolecules it engulfs, including peptides, nucleic acids, carbohydrates, and lipids (lysosomal lipase). the enzymes responsible for this hydrolysis require an acidic environment for optimal activity. hope i !

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.