Fill in the blank with the best word to complete the sentence.
the system is a group of proteins in the blood that attack pathogens that enter the body and kill them.

The correct word for the blank is complement.

The complement system present in the human body can be defined as the group of proteins in the blood that attacks the pathogen that enters the body and kills them.

This is a part of immune system that increases the ability of the proteins to move in the blood stream and has the ability to clear the harmful microorganisms that can cause disease in the body.

you can have just about every answer you can think of