Q4. A couple already has two daughters. What is the chance that their next child is a son?
½ in the simplified chromosome model; earlier children do not change that probability. It is an expectation, not an exact observed population birth ratio.
Q5. How many chromosomes does a worker honey bee have, and is it haploid or diploid?
32; it is a female from a fertilised egg, so it is diploid (NCERT page 71).
Q6. Name the type of sex determination in each: (a) grasshopper, (b) humans, (c) birds, (d) honey bee.
(a) XO type, (b) XY type, (c) ZW type, (d) haplodiploid, by the number of chromosome sets (NCERT pages 70–71).
Q7. In the typical human XY system, is the Y-chromosome larger or smaller than the X, and do males and females have the same number of chromosomes?
The Y is distinctly smaller than the X, and both sexes have the same number of chromosomes, with the same number of autosomes (NCERT page 70).