Answer:
The number of valence electrons increases from left to right.
Explanation: The number of valence electrons increases going across a period, or row in the periodic table, for example, group 1 elements have 1 valence electrons and group 2 elements have have 2.
An astronomical unit (AU) is the average distance between the Earth and the Sun
Answer:
B
Explanation:
If something says always, you have to know for sure that it's true otherwise don't pick it. Covalent compounds have non-metals like carbon(s), oxygen(g), and bromine (l)
I believe that the answer would be D, both the speaker and the microphone
Photosynthesis will produce oxygen gas that will be taken up by humans for respiration. Respiration will produce carbon dioxide that will be taken up by plants for photosynthesis. So both waste products will be recycled and reused so therefore an example of zero waste world