Which best describes how CO2 is absorbed in the ecosystem? a) autotrophs via photosynthesis
b) heterotrophs via respiration
c) fossil fuels via burning
d) detrivores via decomposition

Autotrophs via photosynthesis.

An autotroph is simply an organism that can produce its own food using light, water, carbon dioxide, or other chemicals. In this case it would be a plant, absorbing CO2 to carry out photosynthesis- producing its own food/energy source

The hawk receives 0.1% energy from the caterpillar although the caterpillar gets eaten by another bird smaller than the hawk first