In autumn, people pile fallen leaves and put them in a compost pile. after several weeks, the pile becomes warm. where does the heat come from?

 The heat comes from the bacteria consuming readily decompose materials and the oxidation process heats up the compost pile from ambient air temperature. Bacteria consume carbon as a source of energy (to keep on eating) and nitrogen to build protein in their bodies (so they can grow and reproduce).

a- multicellular

b-eukaryotic

c-no cell wall

d-heterotrophic

e-autotrophic