c. Birth rates are high
Explanation:
A wide base in the population pyramid shows that there is a large population of young people with high fertility rate or birth rate and high death rate.
From the graph, it can also be concluded that narrow tip at the top shows that lesser older people are in the population.
This pyramid shown in the diagram is a triangular age pyramid. In this type of pyramid the pre-reproductive individuals are high reproductive individual are moderate and non-reproducing individual is less. In such pyramid we find population grows.
Suppose in a family of ten 6 are pre-reproductive, 2 moderate reproductive and 2 post-reproductive. We will see the in the course of moderate and post-reproductive will die and those six of pre-reproducing age will increase the population.
The answer is mechanical weathering
