Answer:
Weather conditions
Explanation:
Food can be limited based on location, however, scientists can control what kind of food it is. Soil can be tested and experimented on. There can be a lot of it and different kinds. Space is fought over because of territories and is limited compared to how many people and animals there are. Weather is not something that can be controlled in an experiment since it is sporadic.
Answer: C
The substance that must come through the cell membrane for the cell to live is nutrients. Cells would die if they did not get nutrients. Nutrients are what keeps the cell running.
Answer:
Y- x+ Y-
Explanation:
when an atom loses electrons the atom the result is a positive ion. when an atom gains an electron, the result is a negative ion
