Question

a ______ is an organism that spreads a pathogen from one host to another.
a tangent
b vector
c human
d vitamin

Explanation:

To solve this, we analyze each option:

• Option a: "tangent" is a mathematical term (related to circles/geometry), not relevant here.
• Option b: In biology (a subfield of Natural Science), a "vector" is defined as an organism that transmits a pathogen from one host to another, which matches the description.
• Option c: While humans can be hosts or transmit pathogens in some cases, the term "human" is too general and not the specific term for this role.
• Option d: "vitamin" is a nutrient, not an organism that spreads pathogens.

Answer:

b. vector