Answer: Biology
Step-by-step explanation:
A forensic scientist named Clark should belong to the field of biology. The person must have the knowledge to detect the presence of poison in the blood.
How much concentration of poison is fatal for human beings. What can be the consequences and there are various types of tests available to detect the presence of poison in blood.
The person must know biology and have a certified degree in science to check whether the victims body has poison in it or not.