The answer to your question is a
Answer:
Greatly affect the population.
Explanation:
Environment and weather of a country greatly affect the population and people of a region because good environment with all resources and suitable weather attract people of other regions toward itself. If the location has plenty of water, vegetation, flat geography and food etc, the people settled in this location and increase occur in population whereas if the area doesn't have any natural resources so people migrate from that area.
Answer: Hydrogen bonds are created between the base pairs in DNA. Adenine pairs with thymine and cytosine pairs with guanine. Adenine and thymine create 2 hydrogen bonds while cytosine and guanine create 3. These bonds are fairly weak so that they can be broken when DNA is replicated (by an enzyme called helicase which unwinds DNA). However despite them being weak they do stabilize DNA's double helix structure as well.