A Only one variable changed
Answer:
Fungus
Explanation:
Some fungus feed on living waste.
Answer: when one is lost, one is formed
Answer:
reactions
Explanation:
Reactions occur when two reactant molecules effectively collide, each having minimum energy and correct orientation. Reactant concentration, the physical state of the reactants, and surface area, temperature, and the presence of a catalyst are the four main factors that affect reaction rate.