Q5. Assertion: growth cannot be taken as a defining property of living organisms. Reason: non-living objects can also increase in size, by accretion on their surface. Are both true, and does the reason explain the assertion?
Both are true, and the reason explains the assertion. (Many adult animals also stop growing in size, yet they are alive.)
Q6. Which two features does NCERT say are characteristics of all living organisms in the opening of Chapter 10?
Growth and reproduction (NCERT page 120).
Q7. Why does NCERT not give viruses a place in classification?
They are not considered truly living, if living means having a cell structure; viruses are non-cellular and inert outside their specific host cell (NCERT pages 19–20).
Q8. How does growth in a multicellular organism differ from an increase in size of a non-living object?
A multicellular organism grows from inside: it makes new protoplasm and its cells divide, increasing both the number of cells and the mass. A non-living object may enlarge by surface accretion, swelling or thermal expansion, without making new protoplasm. Size increase alone therefore does not establish biological growth.
Q9. Where in the cell do the chemical reactions that keep it in the living state mainly go on?
In the cytoplasm, which NCERT calls the main arena of cellular activities (page 88).
Q10. Is the growth of plants determinate or indeterminate? What does this mean?
Indeterminate in higher plants (NCERT page 178): they keep growing throughout their life, at their meristems.
Q11. Name the three defining features of living organisms, and two features that are not defining on their own.
Defining: cellular organisation, metabolism and response to surroundings (consciousness). Not defining on their own: growth and reproduction.
Q12. A unicellular organism divides into two. Has it grown, reproduced, or both?
Both: in a single-celled organism, cell division increases the number of individuals (reproduction) and the number of cells (growth) at once.