Red blood cells are considered
because they're highly specialized.

The “ecological footprint” left by a citizen of a developed nation is about four times larger than that left by a citizen of a developing nation. why is this the case?

Which organisms udergo photosynthesis

Deserts (especially true deserts) are not easy places for animals to live. animals who live in them often have special features that them survive. which adaptation would be for this group of animals? a) keen eye sight b) short, narrow legs c) tolerate heat d) webbed feet