Answer:
50%
Explanation:
because 50% comes from the male and 50% from the female
Here you need to put if you have any questions about the material you are learning. If you have none i would consider putting that you have none.
Sweating
It does not involve the respiratory system.
Answer:
Mammals first appeared
Explanation:
The dinosaurs became extinct one million years after the Cenozoic era started. The mammals first appeared as the modern culture first appeared in that era.