Pls help me pls

If the birth rate of a population of dolphins is 2.0, the death rate is 0.5, and the population size is 100, what is this dolphin's population growth?

Other than earth, is also known to have magnetic pole reversal? a: venus b: mars c: earths moon d: the sun

What is the main function of the central vacuole in a plant cell? a. absorbs energy from the sun to produce food b. holds water and maintains turgor pressure c. breaks down molecules to release energy d. contains the cell's genetic material