Which radioactive isotope is commonly used for dating relatively recent fossils (up to about 50,000 years old)? MCQ with Answer and Explanation

Explanation:
ANP is secreted by atrial muscle cells of the heart in response to stretching (high blood volume). It promotes sodium and water excretion, lowering blood pressure. Kidneys secrete renin, adrenal aldosterone, liver angiotensinogen.

Explanation:
All chordates, at some point during their larval or adult stages, possess three key features: a dorsal hollow nerve cord, a notochord (a flexible rod supporting the body), and pharyngeal slits. The notochord may be replaced by a vertebral column in vertebrates. Arthropods have a ventral nerve cord and open circulatory system.

Explanation:
Producers (autotrophs like green plants) form the first trophic level and the base of all food chains, converting solar energy into chemical energy. Decomposers (bacteria and fungi) break down dead organic matter and waste, releasing essential inorganic nutrients back into the soil for producers to use, thus completing the nutrient cycle. Energy flow in an ecosystem is strictly unidirectional, moving from the sun to producers and then to consumers, and is eventually lost as heat; it does not flow bidirectionally. Thus, statements 1 and 2 are correct.