the answer is conduction - the transfer of heat to an object through contact
<span>Answer:
There are only two real sources of energy on the earth. One comes from geothermal from the creation of the earth and the other comes from the sun. You can say wind and nuclear or water, but water's movement is related to the tectonic activity and shaping of the earth and its spin, wind comes from unequal heating of the earth by the sun and nuclear energy comes from isotopes that were formed by a star. So producers are able to harness one of those two energy sources, the sun. Trees and plants are so common because they are using free energy, they have discovered a way to get something for nothing essentially. Predators can use the nutrients they make to supply their own energy but in the end everything boils down to the producers ability to make energy from the sun.</span>
The image shows a phospholipid bilayer. Macromolecules that make up most of the structure that is shown are proteins and lipids. Lipids can make up 20% to 80% of the membrane depending on the location and type of the cell. The rest is made up of proteins.
If the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume. When this happens, the cell must divide into smaller cells with favorable surface area/volume ratios, or cease to function. That is why cells are so small.
simpler answer: Cells are small because they need to keep a surface area to volume ratio that allows for appropriate intake of nutrients while being able to eliminate the cells waste.
