Which of these pairs of body structures best illustrates a homologous relationship

Hello. This question is incomplete. The complete question would be:

"Which of these pairs of body structures best illustrates a homologous relationship

A) the leg of a horse and the leg of a dog , B) the wing of a bat and the wing of a bird , C) the fin of a dolphin and the fin of a shark , D) the beak of a bird and the beak of a turtle"

A) the leg of a horse and the leg of a dog

Explanation:

The homologous organs are those that may or may not perform the same function, but have the same basic structure and even embryonic development. This means, therefore, that individuals with these organs have shared ancestry. As an example we can mention the horse's leg and the dog's leg which are similar structures that have the same function, which is locomotion.

answer; ///as energy flows through an ecosystem,energy (decreases) at each

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.