Answer: Enzymes help speed up chemical reactions in the human body. They bind to molecules and alter them in specific ways. They are essential for respiration, digesting food, muscle and nerve function, among thousands of other roles.
These preparations are called Vaccines. A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing micro-organism and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins.
The correct sequence is option (c)
All the living organisms in the world responds to the environmental conditions and that condition could be temperature, pressure, etc. The changes in the environmental conditions are first observed by the cells of the body and then by the tissues and then from tissues it gets transferred to the organ then to organ system and finally the organism responds to the change.