Final answer:
The term for an event where many types of living things disappear at the same time is a) Extinction, which refers to the death of the last individual of a species, leading to its complete disappearance from Earth.
Step-by-step explanation:
The term for an event where many types of living things disappear at the same time is a) Extinction. An extinction event is defined as the disappearance of a species from Earth when the last individual of that species dies out. It's important to differentiate between the normal rate of extinction, often referred to as the background extinction rate, and mass extinctions. Mass extinctions are significant events in Earth's history where majority of species are wiped out within a relatively short geological time period. Human activities, such as habitat destruction, the introduction of exotic species, and over-harvesting, have notably increased the current rates of extinction.