The hormone aldosterone, which acts on the distal convoluted tubule and collecting duct to increase sodium reabsorption and potassium excretion, is secreted by the: MCQ with Answer and Explanation

Explanation:
Ribosomes are the only organelles common to both prokaryotes and eukaryotes, though sizes differ: 70S in prokaryotes, 80S in eukaryotes. Nuclear membrane, mitochondria, and Golgi are absent in prokaryotes. Ribosomes are the site of protein synthesis. This commonality supports the universal role of protein synthesis in all life forms. Mycoplasma, the smallest prokaryote, also has ribosomes.

Explanation:
Enzyme activity depends on pH and temperature; they are not consumed (reusable). Optimum temperature varies; human enzymes around 37°C, but bacterial enzymes can be higher. So 2 is not universally true.

Explanation:
Testosterone, produced by Leydig cells in the testes, promotes development of male characteristics like facial hair, deepening of voice, and muscle growth. It also regulates spermatogenesis.