If I remember them correctly, the organisms are a fish, a reptile a bird and a human during embryonic development. B & D are the correct answers.
All I know is that stem cells are made in the bone marrow, and they differentiate into red blood cells
The answer is C.blood because bones are connected to tissues. Fats are near tissues and the neurons can be found inside the tissue. Hope this helps.
Answer:
they usually move in the same directions as the sun, but from time to time they seem to slow down stop and reverse direction.
