The normal Glomerular Filtration Rate (GFR) in a healthy adult is approximately: MCQ with Answer and Explanation

Explanation:
In a closed circulatory system (e.g., humans, annelids, cephalopods), blood is always enclosed within vessels (arteries, veins, capillaries) and is distinct from interstitial fluid. Open systems (arthropods, most mollusks) have hemolymph bathing organs in sinuses. The lymphatic system returns fluid to blood. A portal system connects two capillary beds.

Explanation:
A food chain represents the flow of energy and nutrients. The first trophic level is always occupied by producers (autotrophs), primarily green plants and algae, which convert solar energy into chemical energy via photosynthesis. The second level is primary consumers (herbivores), the third is secondary consumers (carnivores), and so on.

Explanation:
The living state and all vital functions first become evident at the cellular level. While macromolecules are present in both living and non-living systems, it is the organized interaction of these molecules within a cell that manifests life. Cells are the fundamental structural and functional units of life.