Q4. Assertion: central diabetes insipidus can cause dehydration when lost water is not replaced. Reason: deficient ADH synthesis or release reduces renal water conservation. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion (NCERT page 242).
Q5. Which hormone is called the emergency hormone or the hormone of fight or flight, and where is it made?
Adrenaline (epinephrine), with noradrenaline, from the adrenal medulla (NCERT page 244).
Q6. Why do the immune responses of old people become weak, according to NCERT?
Because the thymus degenerates in old individuals, less thymosin is produced, and as a result the immune responses of old persons become weak (NCERT page 243).
Q7. Which structure secretes mainly progesterone after ovulation?
The corpus luteum, formed from the ruptured follicle (NCERT page 246).