Develop and growth
• Where the embryo develop?
• oviparous---- embryo develop in egg outside parent body
• Ovoviviparous---- embryo develop within mother body, but depend on the yolk sac of egg eg. Some Shark.
• Viviparous----embryo obtain nutrient from mother during development—most mammal, some shark, some insect, some bony fish, some amphibian and some reptile--snake,
▫ in placental mammal use placenta—specialized organ enable the exchange of respiratory gas, nutrient and waste between mother and developing young.