Skill Builder Practice Science

A group of students observe some sea stars (also known as starfish) while on a field trip. A sea star is

shown in the picture above.

Most of the sea stars have five arms, but two of the sea stars each have an arm that is much shorter than

their other arms. A park ranger tells the students that

the shorter arms were once missing because they were probably eaten by a fish or a crab, but the arms have started to grow back.

Which of the following best describes how sea stars are

able to regrow their arms?

• Sea stars learn how to regrow their arms.

• Sea stars inherit the ability to regrow their arms.

• Sea stars eat food that causes their arms to regrow.

• Sea stars move to warmer water that causes their arms to regrow.

Assertion A: A supersaturated solution crystallizes as it cools.

Reason R: The solubility increases as the temperature decreases.

• Both Assertion A and Reason R are true and Reason R is correct explanation of Assertion A

• Both Assertion A and Reason R are true but Reason R is not correct explanation of Assertion A

• Assertion A is correct but reason R is not correct

• Assertion A is not correct but Reason R is correct

3 ice cubes of similar shape and size were kept on three different surfaces - glass, copper and concrete. The first to completely melt was the cube on the copper surface, while the one on the glass surface melted last. Arrange Copper, Glass and Concrete from WORST heat conductor to BEST.

• copper, glass, concrete

• glass, concrete, copper

• copper, concrete, glass

• concrete, copper, glass

For every kilogram of their body weight, babies need about three times as much protein as adults. What could be the reason for this?

• Their bodies must get used to eating protein.

• Their bodies are growing rapidly and building new protein tissue.

• Proteins help their bodies to get adjusted to food other than mother’s milk.

• Their bodies waste more protein because they cannot digest protein properly.

A typical displacement reaction can be written as follows:

AB + C → A + BC

Which among the following is a displacement reaction?

• H2SO4 + Fe → FeSO4 + H2

• 2H2O → 2H2 + O2

• H2 + Cl2 → 2HCl

• CO2 + H2O → H2CO3

The power has just gone off in Sarita's house and she lights a candle. She decides to place it in front of a mirror as she believes it will light up the room more. Is she correct?

• Yes, the room will receive more light.

• No, since the source is one candle only.

• No, because of the extra shadows.

• It depends on the brightness of the candle.