Chemicals that lower the energy need to start a chemical reaction are called

enzymes

Explanation:

lower the level of energy that needs to be invested in a chemical reaction. A chemical reaction's activation energy is the “threshold” level of energy needed to break the bonds in the reactants.

it's the cell cycle, but cytokines is when the cell divides.

theres 3 stages interphase,mitosis,and cytokines.

interphase prepares the cell for division.

mitosis is the process of dividing the cell,it has 4 parts interphase,anaphase,metaphase,and telophase.

lastly there's cytokines,that's when the cell divides into 2 daughter cells

the missing space is phylum