The answer is c because something that is semipermeable only lets a few things pass through it
1. Homo neanderthalensis, and Homo Sapiens idaltu.
Answer:
1. pituitary glands 2. placenta 3. much larger 4. the lining of the uterus is shed, which is called a period
The arrow will always follow the flow of energy - it will lead to where the energy is going.