Consider the following statements about proteins: 1. They are made of amino acids. 2. Peptide bonds link amino acids. 3. Hemoglobin is a transport protein. Which of the above is/are correct? MCQ with Answer and Explanation

Explanation:
Natural selection is the process where organisms with traits better suited to their environment are more likely to survive and reproduce, leading to adaptation of the population over time. Mutations, which are random changes in the DNA sequence, are the ultimate source of all new genetic variation upon which evolutionary forces act. Evolution is a population-level phenomenon, defined as a change in allele frequencies over generations; it does not occur within a single individual's lifetime. Thus, statements 1 and 2 are correct.

Explanation:
Coral reefs grow by accumulation of calcium carbonate skeletons secreted by living coral polyps, but the reef structure itself is non-living. It increases in mass externally (accretion). Mushrooms, mango trees, and bacteria exhibit intrinsic growth by cell division, characteristic of living organisms. Thus, coral reef growth is non-living accumulation.

Explanation:
Pinocytosis ('cell drinking') is a form of endocytosis where the cell membrane invaginates to take in a small droplet of extracellular fluid and dissolved solutes. Phagocytosis is 'cell eating' of large particles, exocytosis is secretion, osmosis is water movement across a semipermeable membrane.