This type of classification used to be used when classifying the protostome organisms.
In this type of organism, the oral cavity develops from the blastophore, the initial cavity in the gastrula, an early stage of the development of the embryo.
Answer: Life span, Life expectancy.
Explanation:
Extinct is correct. When no members of a species remain, the species is said to be extinct.
Answer:
great grandparents or ancestors
Explanation: