1) a decrease in the amount of groundwater.
Answer:a
a possible explanation for this occurrence is that a test tube or dropper was accidentally used repeatedly without being sterilized, causing sample cross-contamination. DNA in this test case did not confirm that the father of the second child was another client of the fertility clinic who had never met the mother...therefore this is a possibility.
Explanation:
Answer:
Due to environmental conditions.
Explanation:
With the passage of time, environmental conditions change which causes the evolution of of four legged land animals from fish like creature. This change occurs due to change in environment. In water, there is no need for legs because fish moves with the help of fins and tail but the organisms that lives on land has legs in order to move from one place to another so we can say that change in the physical structure of organism occurs due to environment.