Consider statements about microorganisms: 1. Bacteria are prokaryotic organisms. 2. Fungi are eukaryotic organisms. 3. Viruses have a cellular structure. Which are correct? MCQ with Answer and Explanation

Explanation:
Essential amino acids are those that the human body cannot synthesize in sufficient quantities and must be obtained through the diet. There are nine essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Glycine, alanine, and serine are non-essential amino acids that the body can produce.

Explanation:
Biochemical Oxygen Demand (BOD) measures the amount of dissolved oxygen required by aerobic bacteria to decompose organic matter in water; high BOD indicates severe organic pollution. Eutrophication is the excessive enrichment of water bodies with nutrients (like nitrates and phosphates), leading to algal blooms and oxygen depletion. Biological magnification is the progressive increase in the concentration of non-biodegradable toxins (like DDT) at each successive trophic level, not a decrease. Thus, statements 1 and 2 are correct.

Explanation:
Grazing food chain begins with producers (plants). Decomposers break down dead matter at all levels; energy decreases at higher levels; producers are plants/algae.