Question

helical ________ widely understood to confer stability and efficiency in the locomotion of a variety of microscopic organisms—including bacteria, eukaryotic algae, and ciliates—bestows similar advantages, albeit via different propulsive modes, to larger oceanic macroplanktons, such as salps. which choice completes the text so that it conforms to the conventions of standard english? a) swimming is b) swimming has been c) swimming, is d) swimming,

Explanation:

The subject "Helical swimming" needs a verb to form a complete - thought. The present - perfect tense "has been" is appropriate here as it shows an action or state that started in the past and continues to the present. Option A "is" in simple present tense doesn't convey the sense of a long - standing understanding. Option C has an incorrect comma placement. Option D is just a noun phrase without a verb and is incomplete.

Answer:

B. swimming has been