Answer:
(A) rate=
Sp
Ss
st
Explanation:
The rate of chemical is a measure of the speed of a chemical reaction.
The measurement of the reaction rate is based on the disappearance of a reactant or appearance of a product with increasing reaction time.
Reaction rate is usually expressed in terms of a change in concentration of the chosen reactant or product per unit of time.
During a reaction, the concentration of the reactant decreases exponentially with time while that of a product increases exponentially with time.
Reaction rate = 
Taxonomy is the science of naming and classifying organisms based on structural comparisons and genetic evidence.
Efferent nerve any nerve that carries impulses from the central nervous system toward the periphery, such as a motor nerve