Answer:
Organisms respond to a signal called a stimulus.
Explanation:
IT'S D becuse none of the other awser choses make sense so ya
Cellular respiration and photosynthesis are essential to the carbon cycle because cellular respiration involves the intake of oxygen o2 and the exhale of carbon-dioxide co2 into the atmosphere. Where photosynthesis uses the carbon dioxide and water to create oxygen and sugars through energy to repeat the cycle. Respiration in general is a process where carbohydrates are turned into dihydrogen monoxide or water and co2(carbon dioxide). Living organisms together throughout the biosphere and atmosphere work together to continue this because carbon itself is an organic substance.
