The ultimate source of energy for most ecosystems is: MCQ with Answer and Explanation

Explanation:
The hypothalamus is a small region in the forebrain that maintains homeostasis by regulating body temperature, hunger, thirst, sleep, and emotions. It also controls pituitary gland secretions. The cerebellum coordinates movement, medulla controls respiration and heart rate, pons relays signals. Hypothalamus acts as the body's thermostat and the link between nervous and endocrine systems.

Explanation:
In the S (synthesis) phase of interphase, DNA is replicated. G2 is preparation for mitosis. Interphase is the longest. Cytokinesis follows telophase.

Explanation:
Insulin is a peptide hormone secreted by the beta cells of the Islets of Langerhans in the pancreas. Its primary function is to lower blood glucose levels (hypoglycemic effect) by promoting the cellular uptake of glucose, particularly in muscle and fat cells, and its conversion to glycogen (glycogenesis) in the liver. Glucagon has the opposite effect.