Answer:
Active uptake (which I think you mean active transport) is important when the concentration gradient is against that of a certain substance, so it doesn't cross the membrane through diffusion or passive transport. It is sometimes necessary if a substance needs to move across a membrane but can't do so due to electrical charge or that there is a substance on the other side of the membrane preventing diffusion.
Explanation:
Wind energy
Hydro power energy
Geothermal energy
Solar energy
Answer:
1. sperm cell
2.testicles
3.egg
4.ovary
5.fertilization
6.fertilized egg = foetus
Explanation:
That would be the sun. Hope this helps.
