A hiker is going to hike a mountain where there are four trails to the top of the mountain. In how many different ways can he hike up and down the mountain?
If the hiker does not want to take the same trail both ways, in how many different ways can he hike up and down the mountain?

Why do you need to classify the size of a particle

Which scenario describes intraspecific, indirect competition? a. a peacock defends its territory against another peacock. b. lions and hyenas compete for the same prey animals. c. a male black bear eats fish in an area of a lake, so other black bears can’t. d. different species of birds fight over spilled popcorn on the ground.

The structure of adenosine triphosphate (atp) is shown here. which statement best explains how energy stored in the chemical bonds of atp can be released.