Answer:
Secondary succession is the series of community changes which take place on a previously colonized, but disturbed or damaged habitat. Examples include areas which have been cleared of existing vegetation (such as after tree-felling in a woodland) and destructive events such as fires.
B. Because they don’t want to see the patients real reaction to the medication to see if it is actually effective
Answer:
The pebbles inside the rock.
Explanation:
The outside of the rock would've formed around the pebbles.
