number 2 energy is flowing upwards. ex grasshopper eats the grass, rat or whatever that is eats the grasshopper, and the hawk eats the rat. energy is going up each trophic level.
number 3. if the grass became polluted, then animals would get pollution in their bodies and at some point would die. eventually the grass would die too. primary consumers such as mouse, rabbit, grasshopper/snails would accumulate the most pollution because they directly eat the grass. whatever that is in the grass goes straight into their bodies.
