Answer:
A breath
Explanation:
When you breathe in you have to let out said breath
Answer:
Moving against the concentration gradient, or in simpler terms, moving from a low-concentration area to a high-concentration area.
Explanation:
This action uses energy, as according to entropy, the substance will move from a higher concentration to a lower concentration, and cells have to put extra energy to pump the molecules / substance up the concentration gradient.
It is mostly used to trigger chemical responses in cells, like in neuron synapses.
Hope this helped!
Specific proteins are made only at certain times in certain cells.
