Can someone help me out and put this in order please?

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)

Achemical that is released by an animal as a signal to other members of the same species is called a pheromone. t or f

Choose the best definition of allele. a. one of several possible versions of a gene, which each produce a different phenotype b. an organism that's purebred for a given trait c. the process of fertilizing a plant with pollen from another plant d. a set of genes that are located on the same chromosome and so are tightly linked