Water is the single source as it provides the electrons by splitting into oxygen and hydrogen. This process happens during the light-dependent reactions.
The correct answer is 2. By a feedback loop.
Hormone levels in the body is regulated by negative feedback mechanism. In this mechanism, a stimulus stimulates the release of a substances. After the effect of that substance its further release is inhibited. This can be understood by an example, the anterior pituitary gland stimulate the thyroid gland to release thyroxin and on increasing the thyroxin in the blood, feedback the hypothalamus and anterior pituitary to inhibit further release of thyroxin from thyroid gland.
The correct answer is gravity.
The planets and other heavenly bodies are attracted towards the earth by the earth's gravity. The pull which is formed by the gravity of earth holds the objects near the earth surfaces. The planets and atmosphere is also kept around the earth's surface by the gravity.
Answer: The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a byproduct.
Explanation:
