Answer;
Volcanic eruption.
Explanation;
Primary succession is most likely caused by volcanic eruption.
it occurs in lifeless areas; such as regions in which the soil is incapable of sustaining life as a result of factors like lava flows, newly formed sand dunes, or rocks left from a retreating glacier.
The other type of succession is called secondary succession which occurs as a response to disturbance; such as forest fire, tsunami, flood, among others.
Primary consumers (such as grazers and browsers) of the biological community will put pressure on the primary producers (these are plants) since the primary producers have limited resources (water) to reproduce due to the drought. The primary producers hence become scarce and cause the primary consumers to compete for limited resources. This causes the primary producers to reduce in population. Reduction in their population causes limited resources for secondary consumers and this cascades up the food web to tertiary consumers.
C <span>less contaminants would flow into the drainage basin</span>
A concentration gradient must exist. hope this helps
