Midterm Science Quiz

Organs are directly made up of what lower level of cellular organization?

• cells

• tissues

• organisms

• organ systems

Answer explanation

Organs are composed of tissues, which are groups of similar cells working together to perform specific functions. Therefore, the correct answer is tissues, as they are the direct building blocks of organs.

Tags

NGSS.MS-LS1-1

NGSS.MS-LS1-3

Which two systems in the human body work together to eliminate carbon dioxide (CO₂) from the body?

• the excretory and digestive systems

• the digestive and circulatory systems

• the excretory and respiratory systems

• the respiratory and circulatory systems

Answer explanation

The respiratory and circulatory systems work together to eliminate carbon dioxide. The respiratory system expels CO₂ from the lungs, while the circulatory system transports it from body tissues to the lungs for removal.

What is different about parasitism compared to the other biological relationships such as mutualism, predation, competition, and commensalism?

• A parasitic organism causes harm to other organisms as a result of the symbiotic relationship.

• The parasite must utilize a host organism that may or may not die as a result of the relationship.

• The host is neither helped nor hurt by the relationship and interaction with the parasitic organism.

• Both the parasite and the host are helped by the relationship and interaction with the parasitic organism.

Answer explanation

Parasitism is unique because it involves a parasitic organism that causes harm to its host, unlike mutualism, where both benefit, or commensalism, where one benefits without harming the other.

Radars can help meteorologists detect clouds and sailors detect submarines. Radars send out radio waves and record their echoes after the radio waves reflect off an object. Two radars send out radio waves with the same frequency. The first radar sends radio waves through the air. The second radar sends radio waves through the ocean. What is true about these radio waves?

• They are visible.

• They are audible.

• They have different speeds.

• They have the same wavelength.

Answer explanation

Radio waves travel at different speeds in different mediums. In air, they move faster than in water. Therefore, the radio waves from the first radar (in air) and the second radar (in ocean) have different speeds.

Tags

NGSS.MS-PS4-2

Which of the following is one of the energy conversions taking place in a campfire?

• heat to light

• heat to kinetic

• chemical to light

• light to chemical

Answer explanation

In a campfire, chemical energy from the burning wood is converted into heat and light. The correct choice, 'heat to light', describes the conversion of thermal energy produced by the fire into visible light.

Modern telescopes make it possible for astronomers to detect planets around distant stars. Why couldn’t astronomers detect these planets before?

• The planets are much closer than the stars they orbit.

• The planets are much larger than the stars they orbit.

• The planets are much farther than the stars they orbit.

• The planets are much smaller than the stars they orbit.

Answer explanation

Astronomers couldn't detect these planets before because they are much smaller than the stars they orbit, making them difficult to observe against the bright light of the stars.

José performs an experiment to determine how much sugar can be dissolved in 250 milliliters (mL) of water at 25°C. He adds 50 grams (g) of sugar at a time to the water while stirring and observes the solution. After adding sugar the eleventh time (550 g), he notes that undissolved sugar has settled to the bottom of the container. He stops adding sugar and ends his experiment. In his lab write-up he concludes that the solubility of sugar in water at 25°C is 500 g per 250 mL. Is his conclusion defensible, and why or why not?

• No, because he did not add sugar enough times.

• Yes, because when he added more than 500 g it did not all dissolve.

• No, because he does not know if any of the final portion of sugar dissolved.

• Yes, because when he added the tenth portion (500 g) all of it dissolved.

Answer explanation

Yes, because when he added the tenth portion (500 g) all of it dissolved, indicating that this is the maximum solubility of sugar in 250 mL of water at 25°C.

Bill left a hammer out in the rain all day. The next morning it had rust on it. Oxygen and a metal chemically combine to form rust. What is rust an example of?

• a mixture

• a solution

• an element

• a compound

Answer explanation

Rust is formed when oxygen reacts with metal, creating a new substance. This process results in a compound, which is a substance made of two or more elements chemically combined. Therefore, rust is an example of a compound.

Tags

NGSS.MS-PS1-1

Which two systems in the human body work together to eliminate carbon dioxide (CO2) from the body?

• the excretory and digestive systems

• the digestive and circulatory systems

• the excretory and respiratory systems

• the respiratory and circulatory systems

Answer explanation

The respiratory and circulatory systems work together to eliminate carbon dioxide. The respiratory system expels CO2 from the lungs, while the circulatory system transports CO2 from body tissues to the lungs for removal.

The validity of scientific theories and laws depends on evidence. Which of the following statements of evidence supports a law rather than a theory?

• Electrons orbit the nucleus of an atom within a certain radius.

• DNA analysis reveals that a modern species is related to an extinct species.

• Seafloor spreading occurs at a rate of three centimeters per year in the mid-Atlantic.

• The amount of matter in a closed system is the same at the start of a reaction as at the end of the reaction.

Answer explanation

The statement "The amount of matter in a closed system is the same at the start of a reaction as at the end of the reaction" describes a law, as it is a consistent observation that applies universally, unlike theories which explain phenomena.

Tags

NGSS.MS-PS1-5