Answer:
c. are renewable
Explanation:
There are many energy sources that the humans have learned to use and exploit. Some resources are non-renewable, while some a re renewable. The non-renewable tend to be cheaper for the time being, and they also tend to produce more energy, but the problem is that the reserves will eventually run out. On the other side, the renewable resources are constantly out there, and they can not be spent, which gives them the advantage on the long run.
The alternative energy sources have been more and more in the focus, especially when it comes to the more developed nations. The main reasons for this are that the fossil fuels will eventually run out, and that they are more environment friendly. This has led to development of technology that is able to harvest energy from the sun, water, and wind, all which are natural resources that are constantly present and can not be spent. Some nations have invested so much in these resources that they have gradually started to replace the fossil fuels, with the end goal being stopping the usage of the fossil fuels totally.
Answer:
Molecule
Explanation:
A molecule is a term that refers to the smallest unit of a molecular compound with the properties of the compounds.
Molecules are like what atoms are to elements.
Every molecule of a compound possess the unique characteristics of the compound thereby typifying it.
The term molecule is often used to denote a covalent compound with a discrete or separate unit.
Answer:
<u><em>Gravity </em></u>
Explanation:
Basically, the sun keeps all the planets in the orbital motion by gravitational alignment. Just as the earth and moon have a similar gravitational pull towards each other. Galileo gave the idea of Copernicus theory. The theory also follows the models of the geocentric model of Ptolemy. Stars are at a fixed position from the sun and far away from the sun. As compared to the earth which is nearby and rotates on its axis from right to left.
