Answer:
C. Genetic Exchange
Enzymes are catalysts that can be used more than once. If a substance needs to get broken down then it can use the corresponding enzyme to attach itself and break it down into simpler substances. After this is gone, the next substance might come up and attach itself to the enzyme like a lock-and-key model.
Therefore the answer is A) Enzymes accelerate chemical reactions without getting used up in the process.
Behavioural genetics is the study of the effects of genes as well as well the environment on the behaviour of the individuals. The scientists who study the Behavioural genetics are known as behavioural geneticists.
In this case Dr. Hakim is studying the influence of genes and the environment on the aggression, which is a kind of behaviour. Hence, Dr. Hakim is a behavioural geneticists, and he works in in the field of behavioural genetics.