Answer:
Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.
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.
To answer specific questions about the natural world
Answer:
C
Explanation:
Ash from the fire helps restore nutrients
Fires clear out the brush along the ground level before they reach the trees, hence clearing the way to prevent larger fires
Eucalyptus and pine only feed after a fire event when the soil is rich
Therefore the odd one out is C