Which of the following is a biopesticide? MCQ with Answer and Explanation

Explanation:
Polymerase Chain Reaction (PCR) is a powerful molecular technique used to exponentially amplify a specific segment of DNA, creating millions of copies from a small initial sample. Gel electrophoresis is a laboratory method used to separate DNA, RNA, or protein molecules based on their size and charge by applying an electric field through a gel matrix. Restriction enzymes are molecular scissors that cut DNA at specific sequences; DNA ligase is the enzyme that joins DNA fragments together. Thus, statements 1 and 2 are correct.

Explanation:
Tubular reabsorption occurs mainly in the proximal convoluted tubule, where essential substances like glucose, amino acids, and most water are reabsorbed into peritubular capillaries via active and passive transport. Glomerular filtration/ultrafiltration is the initial passive filtration of blood. Tubular secretion adds substances like H⁺ and K⁺ to filtrate.

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.