In the passage given below, there are 5 blanks, each followed by a word given in bold. Each blank has four alternative words given in options (1), (2), (3) and (4). You have to tell which word will best suit the respective blank. Mark (5) as your answer if the word given in bold after the blank is your answer. i.e. No Change Required.

Although the __(A)__  [sheltering] of fish is a familiar form of animal social behaviour, how the school is formed and maintained is only beginning to be understood in detail. It had been thought that each fish maintains its __(B)__ [imposition] chiefly by means of vision. Our work has shown that, as each fish maintains its position, the lateral line, an organ __(C)__ [intransitive] to transitory changes in water displacement, is as important as vision. In each species, a fish has a “preferred” distance and dangle from its nearest neighbor. The ideal separation and bearing, however, are not maintained rigidly. The result is a probabilistic arrangement that appears like a random aggregation. The __(D)__ [dependency] of the fish to remain at the preferred distance and angle, however, serves to maintain the structure. Each fish, having established its position, uses its eyes and its lateral lines simultaneously to measure the speed of all the other fish. It then __(E)__ [latches] its own speed to match a weighted average that emphasizes the contribution of nearby fish.

The correct word here is 'sensitive.' It means 'quick to detect or respond to slight changes, signals, or influences.' This perfectly fits very we talking about sensory organs of a fish. So option 1 is correct. Intransitive means 'without a direct object.' This is completely out of context. 

Accountable: Answerable

Known: Popular

Evolved: Developed