In Squids, the Visceral Mass Is Surrounded by a Thick

In squids, the visceral mass is surrounded by a thick, muscular fold of the body wall called the mantle. The mantle also encloses a cavity, which contains the gills and opens directly to the external environment just behind the head. Squids move by drawing water into the mantle and then forcefully expelling it, which accelerates the animal in the opposite direction.
The mantle has two opposing sets of muscles; radial muscles, which extend from the inner to the outer edge of the mantle, and circular muscle, which wraps around the circumference of the mantle, perpendicular to the radial muscles. Contracting the circular muscle decreases the diameter of the mantle cavity. Contracting the radial muscles decreases the thickness of the mantle.
In jet propulsion in a squid, when water is forced out of the mantle cavity, you would expect

A) that both circular muscle and radial muscles would be contracted.
B) that both circular muscle and radial muscles would be relaxed.
C) contracted circular muscle and relaxed radial muscles.
D) the order of contraction is dependent on the direction in which the squid travels.
E) contracted radial muscles and relaxed circular muscle.

Correct Answer:

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