Use of chemical fertilizers
Chloroplasts. They are only in green plant cells, so, unless you are a green plant, humans and flatworms would not contain them.
Different systems<span> of the body have different functions. For example, your </span>digestive system<span> is responsible for taking in & processing food, while your </span>respiratory system—working<span> with your</span>circulatory system<span>—is responsible for taking up oxygen and getting rid of carbon dioxide. Hope this helps</span>
It's an animal cell because it doesn't have a cell wall or chloroplasts. It's also not rectanglular shaped. :)
Using kilometers in space is useless, as the distances between objects is drastically incred. A lightyear is 9.5 kilometers. It is simpler to say "Alpha Centauri is 4.1 light years away" than it is to say "Alpha Centauri is 28.95 Trillion kilometers away"<span />
