Plz hurry i need these answers fast
based on the graph the dependent variable is

a) time.

b) the number of days.

c) the month of the year.

d) the population of birds.

i put population

Explanation:

Dependent variable is something that can be measeured you wouldnt measer the days or months first but it makes sence to measure the bird population. (it also says in the title that they are studying the bird population and a word also used for study is measure.)