Practice Questions

Read the given passage and answer the following question:

Sea anemones look like plants, but they actually are predatory animals. They are invertebrates, which means that they do not have a skeleton. To protect themselves, they will attach to firm objects on the sea floor, such as rock or coral.

Sea anemones can alter their body shape according to changes in their environment. For example, when ocean currents are strong, the sea anemone will reduce its internal volume in order to decrease the surface area that is exposed to the current. Sea anemones are dependent on water flow for food and nutrients and also for assistance in eliminating waste.

Most anemones share a symbiotic relationship with marine algae called zooxanthellae. These are photosynthetic organisms whose waste products are a food source for the sea anemone. The sea anemone also enjoys a mutualistic relationship with the clownfish. This fish is immune to the stinging tentacles of the sea anemone, and it helps the anemone by actually cleaning the tentacles. The cleaning process yields food for the clownfish, while it remains protected from potential predators by the sea anemones stinging tentacles.

The figure given below shows a cross-section of portions of the internal anatomy of a sea anemone.

According to the given figure, the sea anemone’s mouth is located:

(A) below the pharynx.

(B) at its center.

(C) near its base.

(D) inside the sphincter muscle.

VIEW ANSWER

Answer: (B) at its center.

Explanation

The figure shows some of the internal anatomy of a sea anemone. According to this figure, the sea anemone’s mouth has located at the center of its body. The other answer choices are not supported by the figure.

According to information in the passage, the sea anemone benefits from the presence of:

(F) both the clown fish and zooxanthellae.

(G) the clown fish only.

(H) zooxanthellae only.

(J) neither the clown fish nor zooxanthellae.

VIEW ANSWER

Answer: (F) both the clown fish and zooxanthellae.

Explanation

The passage states that zooxanthellae “are a food source for the sea anemone.” The passage also indicates that the clownfish “helps the sea anemone by actually cleaning the tentacles.” This best supports answer choice F.

Which of the following statements about the sea anemone is supported by the passage?

The sea anemone most resembles:

(A) a clown fish.

(B) a flower.

(C) marine algae.

(D) a rock.

VIEW ANSWER

Answer: (B) a flower.

Explanation

The passage starts out by saying that sea anemones look like plants. Also, the figure shows that a sea anemone looks more like a plant or a flower than an animal. Nothing in the passage suggests that a sea anemone looks like a clown fish, marine algae, or a rock.

Suppose that a strong storm stirred up the water in which a sea anemone was living. The sea anemone’s response would most likely be:

(F) to expose itself to the strong current.

(G) to seek the protection of a clown fish.

(H) to reduce its internal volume.

(J) to detach itself from the seafloor.

VIEW ANSWER

Answer: (H) to reduce its internal volume.

Explanation

According to the passage, “when ocean currents are strong, the sea anemone will reduce its internal volume in order to decrease the surface area that is exposed to the current.” This best supports answer choice H.

As shown in the figure, the part of the sea anemone’s anatomy that connects its mouth to its gastrovascular cavity is the:

(A) oral disk.

(B) tentacle.

(C) pharynx.

(D) sphincter muscle.

VIEW ANSWER

Answer: (C) pharynx.

Explanation

The figure clearly shows that the sea anemone’s mouth is connected to its gastrovascular cavity by way of the pharynx. The other answer choices are different internal parts of the sea anemone, but they do not correctly answer the question.