What is the survival rate of frogs and toads in terms of their eggs reaching maturity?

• A. All eggs survive to adulthood.
• B. Most eggs fail to hatch.
• C. Nearly half of their eggs reach maturity and return to the water to lay their own eggs.
• D. None reach maturity.

Answer: (C)

Frogs and toads produce very large numbers of eggs in water because the environment is full of dangers for every stage of development. Eggs hatch into tadpoles, which face predators, competition for food, and changing conditions, and many do not survive to become adults. Because of this high early mortality, the proportion of eggs that make it to reproductive maturity is a minority, though not zero. Among the given options, the statement that nearly half of the eggs reach maturity and return to the water to lay their own eggs best reflects the idea that a substantial portion can survive to adulthood and reproduce, despite the many losses earlier in life. The other choices are too extreme or inaccurate: not all eggs survive to adulthood, not most eggs fail to hatch in general, and none reach maturity is false. Survival rates vary by species and environment, but the general pattern is large initial numbers with significant but not total mortality, leading to some eggs eventually producing new generations.