Answer:
Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the limitations imposed by practicality, regulation, safety and cost.
Or,
the person who design and builds or maintain machines or structure..
"Grandmother cells" are mostly closely associated with specificity coding. Specifity coding is the representation of particular objects in a particular environment by the firing of neuron that are tuned to respond specifically to that object. Single cells fires only in response to the presence of a particular face say a grand mother but no response to any other face.
The best answer is B - Proteins.
Proteins make up enzymes, or to put it another way enzymes are made up of protein. It is enzymes that speed up the chemical reactions. Enzymes are organic catalysts, substances that speed up a (biochemical) reaction but do not take part in the reaction and remain unchanged at the end of the reaction.
In man, there are many enzymes. The majority of these are found in the digestive system where they greatly aid the process of food breakdown from complex molecules to simple molecules. Examples include salivary amylase found in saliva, which begins the gradual breaking down of starch into glucose right from the moment food is placed in the mouth and mixed with saliva. Pepsin in the stomach breaks down protein.
Bone marrow transplant i think. I hope this helps but im not 100% sure