Answer:
1649 years
Explanation:
It took 1649 years for the world population to double, going from . 25 billion people to . 50 billion people
1. Well developped offspring, and portable baby food despencing. Mamalian young are generally quite well developed when they are born, and the parent does not need to find any specific types of food for the new born since the mother already provides te perfect nutrition.
2. Internal heating allows mammals to remain quick and active in cold climates.
3. Fur is really effective and cheap to produce.
Explanation:
If the concentration of molecules outside the cell is very high relative to the internal cell concentration, the rate of diffusion will also be high. If the internal and external concentrations are similar (low concentration gradient) the rate of diffusion will be low.
What are the living conditions like for all the animals except the pigs and dogs?