Explain the difference between variation and competition.

Tall, cone-shaped mountains in which layers of lava alternate with layers of ash are called a. shield volcanoes. b. cinder cone volcanoes. c. composite volcanoes. d. lava plateaus. select the best answer from the choices provided a b c d i need asap

Which of the four major uses is predicted to change the least by 2020?

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