How come plant cells have a cell wall but our cells don't?

If an organ has six haploid chromosomes,how many chromosomes are present. 6 12

All ova contain sex chromosomes corresponding to: x y xx xy

Which is an example of a vestigial structure? a: paw of a lionb: wing of a birdc: appendix of a humand: tail of a cat(i think it's a but i'm not sure)