Answer:
if its a couple with a trans man (female to male) they can have a baby if they havent had surgery.
a trans woman (male to female) can also have a biological baby with a woman if they havent had surgery.
They could also have had a baby in a past relationship though it wont be biological to the other parent.
The answer is D) proteins
<span>Invertebrates means having no backbone.</span>
