Background Paragraph: Fish reproduce sexually. They lay eggs that can be fertilized either inside or outside of the body. In most fish, the eggs develop outside of the mother's body. In the majority of these species, fertilization also takes place outside the mother's body. The male and female fish release their gametes into the surrounding water, where fertilization occurs. Female fish release very high numbers of eggs to increase the chances of fertilization. 
Story: Two brothers learned about animal reproduction, Tim learned about fish reproduction, while Bill learned about mammal reproduction. They both received grade A. 
Question: Which brother studied less about eggs developing outside of the mother's body?
Bill.