Answer:
For a limb to regenerate, you need bone, muscle, blood vessels and nerves. There are adult stem cells, a kind of undifferentiated cell that can become specialized, that regenerate muscle, but they don't seem to activate.
I also believe the answer is A.
Biomes in the temperature zone have been changed the most by human activity.
We can define biomes as the community or group of animals and plants that are distributed or categorized on the basis of common characteristics of environment they are in, five<span> major types of biomes are aquatic, desert, forest, grassland, and tundra.</span>