Rainforest cover only 2 % of the total surface area of the Earth but in spite of that about 50 % of plants and animals that live on the Earth live there.
By definition rainforests are forests that recieve high amounts of rainfall so you can actually find rainforests in Alaska for example (other examples: Canada, Asia, Africa, Latin and South-America)
About 1/4 of natural medicines are found in rainforests. 70 % or more of the plants that are used to treat cancer are found only in tropical rainforest on the planet.
Trees in tropical rainforests are so dense that it takes approximately 10 min for the rainfall to reach the ground from canopy.
There are 4 electrons altogether shared between carbon atoms in a molecule of C2H4, to be more precise there are 2 electron pairs shared between the carbon atoms.
Answer:
Cells in a large multicellular organism communicate with each other by chemical signals. These signals are passed from one cell to another. To receive and respond to a chemical signal, a cell must have a <u><em>receptor</em></u> for that chemical.
Explanation:
To generate a physiological response, all cells in the body have special proteins called receptors. These receptors are involved in detecting a chemical signal and generating a response. The receptors are specific for different kind of chemical signals. For example, a dopamine receptor will bind a dopamine molecule whereas an insulin receptor will be able to bind an insulin molecule. Apart from chemical signals, some cells might also respond to mechanical signals.
<span>A spider is small enough that its weight can be supported by surface tension, the relatively weak forces that hold water molecules together. </span>Water molecules "bond"<span> to other water molecules around them in all directions, so they tend to stick more strongly to their neighbors, forming a film-like layer across the surface</span>
