Answer: You can tell when a chemical reaction is taking place because it is usually accompanied by easily observed physical effects, such as the emission of heat and light, the formation of a precipitate, the evolution of gas, or a color change. All these things characterize what you look out for to find a chemical change.
Explanation:
correct AnswerAnswer:
D- D and A
Explanation:
REAL EXPLANATION
<h3><em>Chloroplasts take energy from the sun ad make it into food by a process called photosynthesis.... it then makes the energy to power the plant..... </em></h3><h3><em>Mitochondrions are called the power house of the cell, powering and letting the cell do its work transporting more energy into the plant....</em></h3>
Any process that exerts a stress on a rock that eventually causes it to break into smaller fragments is a type of mechanical weathering.
