Wolves prey on a variety of different animals. Since wolves live in packs, they are highly efficient in hunting larger prey. The graph below shows the wolf population in Wyoming between 2000 and 2015.
Modified from image courtesy of NPS
Which of the following could best explain what happened to the wolf population in Wyoming between 2007 and 2009?
A.
There was an increase in the birth rate of wolves.
B.
There were more bison on which the wolves could feed.
C.
There were fewer elk on which the wolves could feed.
D.
There was a larger habitat available for the wolves to live in.
C. There were fewer elk on which the wolves could feed.
Coal is a nonrenewable resource that is mined from the ground. Coal has been used by humans as a major source of energy production since the Industrial Revolution in the 1800s. Which of the following must be true about the Earth's supply of coal?
A.
The supply of coal is constantly being renewed.
B.
The supply of coal has not changed since the 1800s.
C.
The supply of coal has decreased since the 1800s.
D.
The supply of coal has increased since the 1800s.
C. The supply of coal has decreased since the 1800s.
The diagram below shows the formation of a volcanic arc. This arc was formed as a result of an oceanic plate moving underneath a continental plate in a subduction zone.
Image courtesy of USGS
Volcanic eruptions result in magma rising from the interior of Earth toward the surface. Lava is magma that reaches the surface of Earth. Magma and lava cool to form solid rocks that contain minerals from deep inside Earth. These rocks include metal ores, which are rocks that contain metallic minerals (such as copper, gold, silver, lead, and zinc).
Based on this information, which of the following is most likely to be true?
A.
The distribution of metallic minerals on Earth cannot change over time because volcanic activity does not occur any more.
B.
The distribution of metallic minerals on Earth is uneven and depends on the geologic processes that occurred in the past.
C.
The distribution of metallic minerals on Earth is evenly spread across all continents because geologic processes occur uniformly.
D.
The distribution of metallic minerals on Earth cannot be predicted due to the inconsistent formation of these minerals.
B. The distribution of metallic minerals on Earth is uneven and depends on the geologic processes that occurred in the past.
The leaves of a plant are made of cells. Each cell has many different cell structures that function together in plant processes. Chloroplasts are cell structures that help in the process of photosynthesis. In this process, chloroplasts use light energy to produce food for the plant. To help chloroplasts absorb more light, the plant grows with its leaves facing upward in the direction of sunlight. Which cell organelle provides the support needed to allow the plant's leaves to be held upright?
A.
cytoplasm
B.
nucleus
C.
mitochondria
D.
cell wall