Facts and observations that can be objectively observed and carefully measured using the five senses are known as . evidence.
b. key concepts.
c. correlatives.
d. spurious factors.

.a. evidence

Explanation:

Is a tangible support that proves that something is factual or true , as a result evidence since it works as a proof is must be something that one can see,touch ,hear ,smell and taste because it is meant to give a tangible proof of how truthful something is. Evidence are based on facts and observations.

answer; (b) capitalism;