Answer:
because the want to reach their destination
For body cells to function properly, the following conditions need to be balanced:
1. BLOOD SUGAR
2. BODY WATER
3. BODY TEMPERATURE.
These three factors have to be in the right proportion for the cells and the body as a whole to function properly and to maintain homeostasis.
Blood sugar is the source of energy in the cell and it is required by all cell for carrying out the normal biochemical reactions in the body. The biochemical reactions in the body use water as a medium of reaction, thus the water balance in the body must be maintained. The body temperature also need to be kept at the normal level or else the normal biochemical reaction of the body will not be able to take place, due to the fact that incorrect temperatures deactivate the enzymes that mediate biochemical reactions.
A microscope is to see smaller things that you can’t see and it is a really good tool.
The first famous natural scientist to determine how plants change with altitude on tall mountains was Alexander Von Humboldt and Aime Bonpland when climbing some very high volcanoes in South America like Chimborazo at well ove 20,000 feet high and they observed that different plants grow at different altitudes as altitude increases so that as the mountain was ascended the new environments of temperature, moisture,etc would become abiotic for the lower plants but acceptable for the higher elevation plants. In these cases in South America, the lower elevations had very warm temperatures and high humidity so would grow tropical plants with probably large leaves like palm trees etc. On the other hand at high elevations the temperature would be significantly decreased and probably humidity decreased too so only rugged plants like say lichens could grow. At intermediate elevations, most likely say pine trees could grow as I know they do at moderate elevations in Honduras for example.