Q5. Assertion: the digestive system is an organ system. Reason: it is made of two or more organs that perform a common function. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion (NCERT page 79).
Q6. Roughly how many cells of each type does NCERT say a Hydra has?
Thousands (NCERT page 79).
Q7. What does NCERT call the discernible trend in the complexity of organs and organ systems?
An evolutionary trend, studied in Class 12 (NCERT page 80).
Q8. Is the liver a tissue, an organ or an organ system?
An organ; it belongs to the digestive system, which consists of the alimentary canal and digestive glands (NCERT page 81).