Consider statements about ecology: 1. A food chain shows the flow of energy. 2. A food web shows interconnected food chains. 3. Decomposers are the primary producers. Which are correct? MCQ with Answer and Explanation

Explanation:
Bacteria are prokaryotes that primarily reproduce asexually through binary fission, a process where a single cell divides into two identical daughter cells. Fungi reproduce both sexually and asexually, but asexual reproduction commonly occurs through the formation and dispersal of spores (like conidia or sporangiospores). Viruses are obligate intracellular parasites; they lack the metabolic machinery for independent reproduction and must hijack a host cell's machinery to replicate. Thus, statements 1 and 2 are correct.

Explanation:
Green plants (producers) always occupy the first trophic level in a food chain. Energy flow is unidirectional, moving from the sun to producers and then to consumers, never returning to the sun. Due to the 10% law of energy transfer, the pyramid of energy is always upright and can never be inverted. Thus, statements 1 and 2 are correct.

Explanation:
Chief cells (peptic cells) in the gastric mucosa secrete pepsinogen, which is converted to active pepsin by HCl. Pepsin digests proteins into peptides. Parietal cells secrete HCl and intrinsic factor. Mucous cells produce mucus that protects the stomach lining. G cells secrete gastrin hormone. Pepsin functions optimally at pH 1.8-2.0. The stomach thus initiates protein digestion.