<span>Trophoblasts
Trophoblasts are cells that make up the external layer of a blastocyst, this is a major source of nutrient for a newly formed organism</span>
The answer is d., nervous tissue that promotes movement in the muscle tissue, triggers the brain on what muscle tissue needs to move, as in walking or lifting weights...
1. the birds call is a behavioral adaptation 2. the animals body temp changing is physical. 3. the birds flying is a behavioral adaptation.
After a mass extinction, the surviving species evolve more rapidly to fill the newly available niches. The correct answer is D.