Science Assessment Flashcards

Which best explains why some traits become more common in a population over many generations?

Answer: Traits that help survival are more likely to be passed on

Natural selection favors traits that improve survival and reproduction, making them more common over time.

In an electrical circuit, which component is used to control the flow of electric current by opening or closing the circuit?

Answer: Switch

A switch opens or closes a circuit, either stopping or allowing electric current to flow.

A student observes layers of sedimentary rock in a cliff. Which layer is most likely the oldest?

Answer: The bottom layer

According to the law of superposition, in undisturbed rock layers, the bottom layer was deposited first and is oldest.

Which process allows fish to obtain oxygen from water?

Answer: They extract dissolved oxygen using gills

Fish use gills to extract dissolved oxygen from water as it passes over the gill filaments.

When a light ray passes from air into glass, it slows down and bends. This bending of light is called:

Answer: Refraction

Refraction is the bending of light as it passes from one medium to another due to a change in speed.

A student wants to test if salt affects the boiling point of water. Which variable should be kept the same throughout the experiment?

Answer: Volume of water used

The volume of water must be kept constant (controlled variable) to ensure a fair test when changing the amount of salt.

Which best describes the role of decomposers in an ecosystem?

Answer: They break down dead organisms and return nutrients to the soil

Decomposers like fungi and bacteria break down dead organic matter, recycling nutrients back into the ecosystem.