They copulate.
Lamarck.
Lamarck.
In a pouch mainly.
Egg -> tadpole -> frog (Note, most fail to develop properly.)
Egg -> tadpole -> frog (Note, most fail to develop properly.)
The Heart.
it's possible
Horses are like most mammals (humans, too) and the unborn develop in a uterus.
The heart is the first organ to develop in a fetus. Together, blood and the circulatory system, that is powered by the heart, form the first organ system.
fertilize egg
The heart is the second organ to develop in the embryo, following the development of the neural tube. It starts to form and beat by about the third week of gestation.