Aprotein channel, like the peripheral and integral proteins in the diagram, is a transport protein that. a. always moves substances against a concentration gradient. b. always moves substances with a concentration gradient. c. serves as a tunnel for specific substances. d. always requires energy from the cell. i'm thinking a or d but i'm not sure.

Interactions between organisms and their environment impact the organism’s overall population. the jaguar panthera onca is the largest cat in north america. it is found in areas across the southwest, including arizona, new mexico, and texas. it is a carnivore that has powerful jaws and sharp teeth and preys on fish, turtles, tapirs, and many smaller mammals. which shows the relationship between the jaguar and turtles?