The technique of growing plants under controlled conditions in a sterile medium is: MCQ with Answer and Explanation

Explanation:
Prolactin, from the anterior pituitary, promotes mammary gland development and milk synthesis. Oxytocin triggers milk ejection. Estrogen and progesterone prepare breasts during pregnancy but inhibit milk secretion.

Explanation:
Antonie van Leeuwenhoek was the first to observe and describe living microorganisms, including bacteria, using his single-lens microscopes. Robert Koch formulated Koch's postulates, a set of criteria to establish that a specific microorganism causes a specific disease. Alexander Fleming discovered penicillin; streptomycin was discovered by Selman Waksman. Thus, statements 1 and 2 are correct.

Explanation:
For an individual heterozygous at two unlinked loci (AaBb), the possible gamete combinations are AB, Ab, aB, ab, i.e., 4 types. This follows the law of independent assortment. Formula: 2^n, where n is the number of heterozygous gene pairs. Here n=2, so 2²=4. If genes are linked, recombination frequency determines the proportion.