Ash trees are key to the health of certain forest ecosystem because they:
a.) consume the most resources
b.) are the largest organisms
c.) live closest to the ground
d.) support many other species

Eukaryotic cells are theorized to have evolved from prokaryotes called the endosymbiotic theory. this explains that the most primitive eukaryotic cell engulfed a prokaryotic cell (by the process of phagocytosis) that is capable of cellular respiration and another prokaryotic cell that is capable of photosynthesis. these prokaryotic cells eventually became organelles and these organelles are the mitochondria and the chloroplast

The direction a chemical reaction occurs is represented by an arrow