Final answer:
Species with many offspring at one time are usually r-selected, which is a reproductive strategy involving high reproductive rates and less parental investment.
Step-by-step explanation:
Species that have many offspring at one time are usually r-selected species. These species are characterized by having a high reproductive rate, with the expectation that not all offspring will survive to adulthood. They tend to mature quickly, have a short lifespan, and invest very little energy in parenting. Examples include dandelions and jellyfish. In contrast, K-selected species are adapted to stable environments and invest more in fewer offspring, which have a greater likelihood of reaching maturity due to parental care and support. Elephants and humans are examples of K-selected species.