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Answer:
C. growth of plants after a forest is destroyed by fire
Explanation:
When the ecological succession occurs on the land or region which was never inhabited by plants previously, the process is called primary succession. On the other hand, secondary succession occurs on land where the existing vegetation was destroyed by some disturbances. Secondary succession is a fast process compared to the primary succession as the soil is already present to support the growth of plants.
Among the given examples, the growth of plants after the vegetation of forest was destroyed by fire represents the process of secondary succession. Growth of vegetation on bare rocks, in the cracks in the concrete surface, or after the melting of glaciers represents the process of primary succession.
To calculate this we will use the light equation:

λ

We have Frequency

.
We know that speed of light in vacuum is

.
Since a unit of speed of light is m/s, we can change the unit of frequency Hz to 1/s, since Hz means cycles per second (f=1/T).
So:

<span>

</span>
<span>

λ

</span>⇒ λ

⇒ λ

⇒ <span>λ</span>
Topsoil is the home of living things and the materials that they make or they change. Some examples of organisms that live in the soil are small animals like moles and earthworms, bacteria, and fungi that mix and break down materials into nutrients for plants, animals, and insects.