Q4. Assertion: during exercise, the rate of respiration and the heart beat both increase. Reason: the energy demand of the muscles rises, so the supply of oxygen must increase. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion (NCERT page 230).
Q5. What does the endocrine system use to integrate the body’s activities?
Hormones: it provides chemical integration (NCERT page 230).
Q6. In NCERT’s three-step comparison, which animals have a better-organised neural system, with a brain along with a number of ganglia and neural tissues?
Insects (NCERT page 231).