Question

noise pollution
what is loud?
decibels, symbolized as db, measure noise intensity levels. the epa and world health organization (who) offer guidelines to prevent hearing loss.
urban areas have various noise sources: transportation, construction, machinery, and household appliances. urban settings tend to be noisier than rural ones due to human - made sounds.
natural noises, while loud, such as thunder and volcanic eruptions are usually brief and don’t contribute to long - term noise pollution.
chart: noise levels with categories like breathing (10 db), rustling leaves (20 db), calling birds (30 db), conversation (40 db), moderate rain (50 db), vacuum (60 db), traffic (70 db), lawn mower (80 db), thunder storm (90 - 100 db)
what is used to measure noise intensity?
options: db, ft, in, k

Explanation:

From the left - hand text, it is stated that "Decibels, symbolized as dB, measure noise intensity levels". So we can find that decibels (dB) are used to measure noise intensity. The other options: "ft" is a unit of length (foot), "in" is also a unit of length (inch), and "K" can represent various things like Kelvin (temperature) or kilo (a prefix), but none of them are used to measure noise intensity.

Answer:

A. dB