Dichotomous Key/Mammalia
Appearance
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1
[edit | edit source]Egg: | A zygote, resulting from fertilization of the ovum |
Birth: | The process by which a fetus is expelled from the body of its mother |
- Birth
- Eggs - Monotremata
- Live birth - 2
2
[edit | edit source]Marsupium: | A pouch in which an animals' young are reared through infancy |
Uterus: | An organ that accepts a fertilized ovum and nourishes it until birth |
Placenta: | An organ that moves nourishment and waste between a fetus and its mother |
- Development of young
- In a marsupium - Marsupialia
- In a uterus with a placenta - Placentalia