Aquatic animals typically use external fertilization because water allows for easy dispersal of gametes and provides a medium for the sperm to swim towards the eggs. External fertilization allows for a high chance of successful fertilization because a large number of gametes can be released simultaneously. In addition, aquatic environments are often vast and unpredictable, with potential mates scattered and not easily found. On the other hand, terrestrial animals utilize internal fertilization because they face more challenges, such as a dry and uncertain environment. Internal fertilization ensures a higher chance of successful fertilization by protecting the vulnerable eggs from dehydration and predators. It also allows for greater control and selectivity in choosing mates.
