Answer: D
Explanation: Everything to the left of the yield, or the arrow, is a reactant (it reacts). Everything on the right side is a product.
The chemical reactions that absorb energy are called endothermic reactions. These reactions absorb more energy than they release. From the given options endothermic reactions are: respiration in cells, photosynthesis, activating a cod pack
The chemical reactions that release energy are called an exothermic reactions: producing electric current, burning a candle, baking bread.
Collisions between molecules increase as the temperature rises. As temperature increases, so does the rate of chemical reaction.
Photosynthesis is the process whereby oxygen is produced and is released into the atmosphere.
Answer: Gemstones of various minerals are highly prized for beauty, durability, and rarity. Some noncrystalline materials of organic origin. Examples are pearl, red coral, and amber also are classified as gemstones. Gemstones have attracted people since the ancient times, and have been used for jewelry.
Explanation: