Which of the following nitrogen bases is present in RNA, but not in DNA? A- U

B- C

C- G

D- A

Select the correct answer. which term do biologists use to describe the average number of individuals of a species per unit area? a. carrying capacity b. population density c. minimal viable population d. survivability curve

Several bird species feed in a certain species of tree. each bird species feeds in a different part of the tree. which statement is true of these bird species? a. they have adapted to different niches due to competition b. they have a carnivorous relationship with the tree species. c. they have adapted to different niches due to predation d. they have a symbiotic relationship with the tree species.

The nervous system interacts with the endocrine system by a. using hormones as connections b. sending nerve impulses directly to glands c. using neuroendocrine cells as connections d. sending neurotransmitters directly to neurons