Answer:
A. Deposition - sediment is set down in a new place
Producers, because they're the start of the food chain and without them there will be no food chain.
<span>1. Introduction of a different environmental pressure, like an invasive species or a prolonged natural disaster.
2. Random mutation, where a gene or set of genes in an individual organism is randomly different from the normal type of that gene in the larger population. This individual may gain an advantage from this mutation and its offspring will inherit the advantageous trait.</span>
