A) T<span>he evolution of multicellular life</span>
I think during mitosis. Cancer fighting cells disrupt during the time when cells are splitting.
The ecological pyramid is smaller at the top due to the lower amount of species to fit into the category (diversity is decreased, and the higher, the more suppressed the energy is in the animals/species).
Mortality, or death rate is a measure of the number of deaths in a particular population, scaled to the size of that population, per unit of the time. In this case a factor that would result to an increased mortality rate in a population due to increased competition of water will be the density-dependent factor.
