Which is a modification into the spine in a cactus plant?

Asmall number of finches are removed randomly from the wild and placed in a protected bird area. they are given as much food as they need and have plenty of space. why would natural selection not occur in this population? a. there is no reason for genetic mutation to occur. b. the birds compete for limited resources, c. the population has not reached carrying capacity. d. there is no genetic variation in the finches.

Hummingbirds drink nectar from flowers, while robins eat plant seeds. what does this reduce?

What is the importantence of the carbon and nitretan cycles in the environment