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

Explanation:
The loop of Henle creates a concentration gradient in the medulla, enabling water reabsorption and concentrated urine. Urine is formed in kidneys, the unit is nephron, ureter connects kidney to bladder.

Explanation:
Xylem vessels and tracheids are dead, hollow cells at functional maturity, providing a continuous tube for water transport. Phloem sieve tube elements are living cells at maturity, though they lack a nucleus, and are responsible for transporting organic nutrients. Cambium (vascular and cork) is a lateral meristem responsible for secondary growth (increase in girth), while apical meristems are responsible for primary growth (increase in length). Thus, statements 1 and 2 are correct.

Explanation:
Clostridium botulinum, an anaerobic spore-forming bacterium, produces a potent neurotoxin causing botulism, often from improperly canned low-acid foods. Salmonella and E. coli cause gastroenteritis from contaminated food/water, Staphylococcus aureus produces enterotoxins causing acute vomiting. Botulism can be fatal without antitoxin.