Evolution of cyanobacteria that produce O2volcanic outgassing to create a thicker atmosphereformation of an ozone layer to block harmful radiationall of the above<span>only a and c
Are the options</span>
The valence electrons of metals are weakly attracted to the parent nuclei, so the electrons break free and float. The moving electrons form a electron <u>negative</u> blanket that binds the atomic <u>positive</u> nuclei together, forming a metallic bond.
So the answers are <u>{ Negative }</u> and <u>{ Positive }.</u>
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a yoyo in someones hand is an example of potential energy
Speed is distance over time, learn that formula and look at the image
Acceleration = (change of speed) / (time for the change)
Change in speed = (22 - 4) = 18 m/s.
Time for the change = 3 sec.
Acceleration = 18/3 = 6 m/s per second.