Answer:
adding chlorine, checking the water.
Explanation:
Because this increases the quality of the water while the rest improve either quantity, or ease of access.
Answer:
I'm pretty sure the answer is natural selection.
Explanation:
Natural selection acts on phenotypic variations in populations.
They both can be traced back millions of years ago
Answer: the correct option is C(communicate through sign language)
Explanation:
Chantek the orangutan is one of many nonhuman primates that scholars have used to draw conclusions about the origins of human language because they seem to be able to communicate through sign language. Taught by American anthropologists Lyn Miles and Ann Southcombe Channel the orangutan learnt how to communicate using that American sign language.