I believe the answer is B. Homoiothermal
For the first question-a bicep is a large muscle in the upper arm which flexes the arm and forearm, a tricep is a large muscle at the back of the upper arm and a deltoid is a thick triangular muscle covering the shoulder joint and used for raising the arm away from the body.
Its b. Ecosystem
Population is the number of a species in an area, it has nothing to do with physical characteristics.
Abiotic is just an adjective meaning not alive
Competition is just the interactions between organisms in the struggle for food, water, space, mates, and many other things again not physical characteristics
