The answer is Grass and Cactus. It will never stop running out of energy to feed the herbivore consumers.
The two cells of the similar shape, and size have different levels of the ongoing metabolic activity. On one hand, the cell a is metabolically quiet, which means that no energy consuming chemical reactions are taking place in this cell. On the other hand, the cell b is actively consuming the surrounding oxygen. In this scenario, the oxygen will more quickly diffuse into the cell b because the diffusion gradient for oxygen in this cell is steeper than in the cell a.
Hence, the blanks can be filled with 'b and the diffusion gradient is steeper' respectively.
Answer:
Option B, electrochemical signals
Explanation:
The first process that initiates the muscle contraction is the binding of calcium ion with troponin protein. After this chemical interaction, the active binding sites of actin gets exposed. After this myosin binds to the actin sites thereby forming a high-energy head bridge and releasing the pi. Mysosin now goes to a lower energy state by undergoing conformational change. This causes power stroke and actin filament is pulled towards the M-line. Later on the muscle contracts by shortening sarcomere.
This entire process is an electrochemical process. hence option B is correct.