Question

read the passage, then answer the question below.

image: a lake sturgeon with barbels under its mouth

at the border between the united states and canada, a series of lakes known as the great lakes forms the largest freshwater system in the world.

the great lakes are home to several species of large fish, such as the spotted gar, the lake sturgeon, and the walleye. lake sturgeon have sensory organs called barbels that hang down from their mouths. the sturgeon swim just above the rocks and gravel at the bottom of a lake. they use their barbels to search for prey including snails, mussels, and worms.

which of the following best describes an ecosystem in the great lakes?

• the lake sturgeon and the walleye
• a school of spotted gar
• the water, the gravel, the snails, and the worms

Explanation:

An ecosystem includes both biotic (living) and abiotic (non - living) components. The option "the lake sturgeon and the walleye" has only biotic components (two fish species). The option "a school of spotted gar" has only biotic components (a group of one fish species). The option "the water, the gravel, the snails, and the worms" includes abiotic components (water, gravel) and biotic components (snails, worms), which fits the definition of an ecosystem.

Answer:

the water, the gravel, the snails, and the worms