The answer would be Waning Crescent :)
No, it is usually caused my moving water, such as heavy rain or rivers or oceans.
Selective permeable means it selects what goes out and comes into the cell. If the cell membrane wasnt selective then things could enter the cell and destroy it.
-Seth
<em>An herbivore is an animal or insect that only eats vegetation, such as grasses, fruits, leaves, vegetables, roots and bulbs. Herbivores only eat things that need photosynthesis to live. This excludes insects, spiders, fish and other animals.</em>
