Science

Buffelgrass is an invasive species of grass from Africa that outcompetes native Texas grasses for space and water. Which long-term change to a Texas grassland would most likely occur due to the introduction of buffelgrass?

• The population of native grasses will increase.

• The population of native grasses will decrease.

• Buffelgrass offspring will develop traits like those of native grasses.

• Buffelgrass offspring will develop traits like those of other invasive species.

Answer explanation

The native grass population will decrease since buffelgrass is competing against it for the same resources.

Tags

NGSS.MS-LS2-4

If the students continue at the same speed, which statement describes the total distance traveled after 90 seconds?

• Student 1 traveled 40 m, and student 2 traveled 20 m.

• Student 1 traveled 50 m, and student 2 traveled 30 m.

• Student 1 traveled 60 m, and student 2 traveled 30 m.

• Student 1 traveled 70 m, and student 2 traveled 25 m.

Answer explanation

Speed is a measure of distance over time. Student 1 travels 40 meters in 60 seconds. Student 2 travels 20 meters in 60 seconds. After an additional 30 seconds (90 seconds total), student 1 would travel another 20 meters for a total of 60 meters, and student 2 would travel another 10 meters for a total of 30 meters.

A star that has a luminosity of 10-2 and a temperature of 20,000 K is most likely a —

• Main sequence

• White dwarf

• Blue giant

• Red giant

Answer explanation

White dwarf stars are found to be around 20,000 K and 10-2 luminosity. The student correctly interpreted the H-R diagram to identify the white dwarfs.

Tags

NGSS.HS-ESS1-3

• allows water to enter and exit the cell

• contains genetic information

• stores water and nutrients

• produces its own food

Tags

NGSS.MS-LS1-1

NGSS.MS-LS1-2

• Because of friction, the ball continues rolling forward at the same speed.

• Because of friction, the ball rolls forward at an increased speed.

• Because of inertia, the ball continues rolling forward at the same speed.

• Because of inertia, the ball rolls forward at an increased speed.

• There is a change in shape.

• There is a change in volume.

• The two liquids mix into a solution.

• The two liquids form a new substance.

Tags

NGSS.MS-PS1-2

• It is August in the Northern Hemisphere. It is April in the Southern Hemisphere.

• It is summer in the Northern Hemisphere. It is winter in the Southern Hemisphere.

• The number of hours of daylight is greater in the Southern Hemisphere than in the Northern Hemisphere.

• Spring begins earlier in the year in the Southern Hemisphere than it does in the Northern Hemisphere.

Tags

NGSS.MS-ESS1-1

Immediately after a forest fire, the primary consumers in the area will compete most for which biotic factor?

• Food

• Space

• Oxygen

• Sunlight

Tags

NGSS.MS-LS2-1

A student pushes a 51.5 kilogram bookshelf across a smooth floor with a net force of 67 N. What is the approximate acceleration of the bookshelf?

• 1.3 m/s2

• 3,450.5 m/s2

• 15.5 m/s2

• 0.77 m/s2

Tags

NGSS.MS-PS2-2

Which pair of elements are nonmetals and gases at room temperature and normal atmospheric pressure?

• Fluorine, F, and chlorine, Cl

• Boron, B, and aluminum, Al

• Hydrogen, H, and cesium, Cs

• Cobalt, Co, and nickel, Ni