I believe the answer is cell theory
Answer:
D. A bicycle rusting.
Explanation:
A. is incorrect because tearing a piece of paper is a physical change, not a chemical change.
B. is incorrect because we are just heating up the object. That only changes how fast the particles are moving and the change in state of matter.
C. is incorrect because we are adding heat to change a state of matter (from solid to liquid) and it is a physical change.
Therefore, only D. is the correct answer. Iron rusts, and when it does, it chemically changes into an iron oxide (rust).
Factors Affecting Enzyme Activity. ... Several factors affect the rate at which enzymatic reactions proceed - temperature, pH, enzyme concentration, substrate concentration, and the presence of any inhibitors or activators.
The density does NOT change. If you have an object and then ylu split it in half, the density does not change, it will be the same.
