Question

the north celestial pole (ncp)—the fixed point around which stars in the northern hemisphere (including the sun) appear to rotate—is discernible only at night. inspired by watching the ncp to navigate using skylight polarization, which occurs as atmospheric particles scatter sunlight, a polarimetric camera captures images of polarization patterns, which vary as the sun’s position in the sky changes; temporal variances across images can then be used to determine an observer’s latitude and bearing relative to the ncp.

8 mark for review
which choice best describes the overall structure of the text?
a it illustrates how most navigational tools utilize the ncp, recounts how researchers discovered that certain animals are able to navigate without using the ncp, and then proposes that this discovery could be used to avoid problems in navigation associated with reliance on the ncp.
b it presents a celestial - based method of navigation, enumerates the comparative benefits of an alternative method used by certain animals that is based on an unrelated natural occurrence, and then indicates how researchers assessed the relative accuracy of the two methods.
c it explains how the ncp is typically located, emphasizes a key difference between how humans and certain animals use the ncp for navigation, and then suggests an alternative way of using the ncp to improve existing navigational instruments.
d it notes an obstacle to observing an astronomical phenomenon, summarizes a navigational ability of certain animals that inspired a solution to that obstacle, and then explains how researchers used an optical device to mimic that ability.

Explanation:

The text discusses a method inspired by animals' navigation using the NCP (North Celestial Pole) and a new method (polarimetric camera) to determine latitude/bearing. Option B presents a celestial - based navigation method (NCP - inspired) and an alternative (polarimetric) used by animals (inspiration) and then compares their accuracies (researchers assessed). Option A is incorrect as it focuses on avoiding NCP - related problems, not the overall structure. Option C explains NCP location and differences but not the alternative method. Option D notes an obstacle to observing astronomical phenomena but the text is about navigation methods, not observing obstacles. So B best describes the overall structure.

Answer:

B. It presents a celestial based method of navigation, enumerates the comparative benefits of an alternative method used by certain animals that is based on an unrelated natural occurrence, and then indicates how researchers assessed the relative accuracy of the two methods.