Answer:
Option B. is the right answer.
Explanation:
Before developing a new technology, an engineer has to evaluate the advantages and disadvantages of the chemical used in order to clean water bodies. If the chemical has more disadvantages as compared to advantages, so its usage will be avoided while if the chemical does not harm the marine organisms of the ocean so it can be used for the purpose of cleaning. So we can say that first the engineer has to study the chemicals.
Lymphocytes, this is the white blood cell that identifies these pathogens
