It is commonly known that our Galaxy rotates upon the sun because of gravity. The diagrams' arrows sort of describe it. Id suggest Gravity as the answer.
A local community needs to provide more electricity for its growing population. Currently, the community's electricity needs are met by coal-burning power plants several kilometres away. Citizens are concerned that burning more coal will produce too much air pollution.
Which of the following could be used as an alternative energy resource to help minimise air pollution in this community?
A. hydroelectric energy
B. solar energy
C. wind energy
<u>D. all of these
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You can know the metal with low reactivity and the metal with high reactivity from the periodic table, as in metals the Chemical reactivity increases by going down a group, because of the farther down group we go the easier of lose and gain of electrons or the easier the electrons to be given or taken, this caused the chemical reactivity be higher.
- and the chemical reactivity decreases as we go across the period because they want to give away valence electrons, they need more energy to get rid of them.
