Answer:

Explanation:
Let's think about this from a human perspective (humans are multicellular organisms).
Humans inhale oxygen to use in cellular respiration. Carbon dioxide is the waste product of the process and it is exhaled.
Humans consume proteins and make proteins in protein synthesis. They are used for all sorts of things such as: hormones, repairing tissues, catalysts, providing structure, and more.
So, clearly, the substance that is let out is<u> carbon dioxide</u>. It is exhaled as waste when we breathe, but proteins are used inside the body.
Lack of clean water is able to complicate health. This could easily cause dehydration in children and adults. If someone is dehydrated, they won't be able to function properly and if they stay like this for long, this can cause a risk of death. Lack of clean water can easily turn into hygiene problems because the child wouldn't have a way to clean themselves or even do something as simple as washing their hands. This can transfer many bacteria only making the children catch illnesses. This, therefore, would prevent them from learning. This also goes for teachers because if the teachers do not have proper hygiene, they won't be able to teach. Once again this would affect children as well because children wouldn't have anyone to learn information. This would result in a bad education.
Answer:
If semen gets in the vagina, the sperm cells can swim up through the cervix and uterus and into the fallopian tubes, looking for an egg. They have up to 6 days to find an egg before they die. When a sperm cell joins with an egg, it's called fertilization. Fertilization doesn't happen right away.
Explanation:
This is how reproduction works.
The answer is b. er packages proteins and delivers them to other parts of the cell.