If the allele frequency of a gene for brown fur is increasing from 15 to 25 percent, the population of the bears is evolving.
I think that it's weathering because weathering is the one that wears down the surface.
The Muscular system. If you look at the human body, you see we're made of layers. 1st layer is the skeleton, the maintains the body's shape, then you have the 2nd layer, the muscular, this provides the ability of movement. And the layers keep going until you get to the skin.
Explanation:
Many invertebrate animals cant survive in water that has been polluted and resulted in a lowering of oxygen concentration so the presence or absence indicates the extent to which a body of water is polluted.
Lichens can be used to indicate air pollution as they grow exposed to places such us rocks and tree barks. They need to be efficient at absorbing water and nutrients to grow there. Rain water contains enough nutrients to keep them alive. Air pollutants dissolve in rain water especially sulfur dioxide can damage lichens and prevent them from growing. This makes them a natural indicator of air pollution.
Answer:
Volcanic mountains form when molten rock from deep inside the Earth erupts through the crust and piles up on itself.
Explanation: