Question

description hypothesis scientific theory scientific law often expressed as an \if...then\ statement usually only applicable to a particular experiment or model system considered universal (in effect everywhere, at all times) describes the relationship between observable phenomena a widely accepted explanation about the natural world

Explanation:

A hypothesis is often an "if...then" statement and usually only applicable to a particular experiment or model system. A scientific theory is a widely - accepted explanation about the natural world. A scientific law is considered universal and describes the relationship between observable phenomena.

Answer:

Often expressed as an "if...then" statement: Hypothesis
Usually only applicable to a particular experiment or model system: Hypothesis
Considered universal (in effect everywhere, at all times): Scientific Law
Describes the relationship between observable phenomena: Scientific Law
A widely accepted explanation about the natural world: Scientific Theory