Living things need energy to carry out their life processes. animals get this energy from food through a
process called cellular choose
the first stage, glycolysis, occurs in
conditions, or without oxygen. the second stage, called the krebs cycle, and the third stage, electron
transport, require the presence of oxygen, and are therefore choose.

a- all cells come from pre-existing cells

the rocks are classified by the geological process they are formed by. the three main groups of rocks are igneous, metamorphic, and sedimentary. minerals are not they are classified under the chemical classes they are in. these groups include silicates, sulfates and carbonates.

c.           is the correct answer