our body tells us we need more energy by feeling hungry (like your stomach is rumbling), and it also tells us by feeling tired. also if your body is short on fluids, you will start feeling fatigued.
Answer:
oxygen, let me know if this helps
Answer:
: Notice the rate of diffusion increases as the concentration gradient increases. If the concentration of molecules outside the cell is very high relative to the internal cell concentration, the rate of diffusion will also be high.
