An Elementary School Science Teacher Decided to Liven Up the Classroom

question 90

Multiple Choice

An elementary school science teacher decided to liven up the classroom with a saltwater aquarium. Knowing that saltwater aquaria can be quite a hassle, the teacher proceeded stepwise. First, the teacher conditioned the water. Next, the teacher decided to stock the tank with various marine invertebrates, including a polychaete, a siliceous sponge, several bivalves, a shrimp, several sea anemones of different types, a colonial hydra, a few coral species, an ectoproct, a sea star, and several herbivorous gastropod varieties. Lastly, she added some vertebrates-a parrotfish and a clownfish. She arranged for daily feedings of copepods and feeder fish.
-The bivalves started to die one by one; only the undamaged shells remained. To keep the remaining bivalves alive, the teacher would have to remove the

• A) sea anemones.
• B) sea star.
• C) gastropods.
• D) ectoprocts.
• E) parrotfish.

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Definitions:

Variance

A measure of the dispersion or spread of a set of values, indicating how much the values differ from the mean of the set.

Deviations

Differences between values in a data set and a central point, typically the mean of the set.

Interquartile Range

A measure of statistical dispersion, which is the spread between the first and third quartiles of a dataset, effectively capturing the middle 50%.

Variance

A measure of the dispersion of a set of values, calculated as the average of the squared deviations from the mean.