It is d because pesticides run off into water, they are absorbed into soil , and they are left in the air , hope this helps :)
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:
Carbon dioxide is a byproduct of respiration while oxygen is a byproduct of photosynthesis.
Remember that a byproduct is a secondary product that is made in the synthesis of another. It is unintended and excreted.
Neurons pumping out the cells of potassium into the cells meaning energy is being transfer