A particle can move without energy in a passive transport process while it does in an active transport process.
Abdominal muscles or acids weakness.
Anxiety is fear of mind function or psychological problem
The best possible explanation is phototropism.
Since the trees are very dense, some plants don't get enough sunlight. A reaction to this is to seek out sunlight. This would result to trees growing taller than the rest in order to obtain sunlight.<span />
<span>Most organisms, including humans, can't use the free gaseous form of nitrogen found in the air. We need other organisms and natural processes to "fix" nitrogen into a solid form that plants and animals can use. Most of the nitrogen that plants and animals use is made by bacteria.</span>
