Which of the following vertebrate undergo external fertilization?

Explanation

This Biology question is asking which type of vertebrate undergoes external fertilization. External fertilization is when fertilization (the fusion of an egg and sperm cell) occurs outside of the body. The options are amphibians, reptiles, birds, mammals, or both birds and mammals. The correct answer is Option A, amphibians. Amphibians are a type of vertebrate that typically lay their eggs in water or moist environments. The male releases sperm onto the eggs, and fertilization occurs externally. Reptiles, birds, and mammals all have internal fertilization, which means that fertilization occurs inside the female's body. Reptiles and birds lay shelled eggs that are fertilized internally, while mammals give birth to live young that have already been fertilized internally. It's important to note that there may be some exceptions to these generalizations, but in most cases, amphibians are the only vertebrates that undergo external fertilization. In summary, the correct answer to this Biology question is Option A, amphibians, as they are the only type of vertebrate that undergoes external fertilization.