HiSET Science Practice Test #2 3

Question 1

What is the difference between a hypothesis and a theory in science?

Accepted Answer

A hypothesis is a testable prediction; a theory is a well-supported explanation backed by extensive evidence

Answer

A hypothesis is a testable, falsifiable prediction made before an experiment. A scientific theory is a well-substantiated explanation supported by repeated testing and a large body of evidence — not a guess.

Question 2

Which force keeps planets in orbit around the sun?

Accepted Answer

Gravity

Answer

Gravity is the attractive force between masses. The sun's gravitational pull on the planets provides the centripetal force that keeps them in orbit rather than flying off in a straight line.

Question 3

Which part of the human nervous system is responsible for voluntary muscle movements?

Accepted Answer

Somatic nervous system

Answer

The somatic nervous system controls voluntary actions — movements you consciously initiate, such as picking up an object or walking. The autonomic nervous system controls involuntary functions like heartbeat and digestion.

Question 4

In a chemical reaction, what is a catalyst?

Accepted Answer

A substance that speeds up a reaction without being permanently changed

Answer

A catalyst increases the rate of a chemical reaction by lowering the activation energy needed. It participates in the reaction but is regenerated at the end, so it is not permanently consumed.

Question 5

What is the primary driver of plate tectonics?

Accepted Answer

Convection currents in the mantle

Answer

Convection currents in Earth's semi-fluid mantle are driven by heat from the core. This movement drags the tectonic plates that sit on top of the mantle, causing them to move apart, collide, or slide past each other.

HiSET - High School Equivalency Test Practice Test

HiSET - High School Equivalency Test Practice Test

HiSET Science Practice Test #2 3