What is found in greater quantities as one gets closer to the equator?

The correct answer highlights that UVB rays are found in greater quantities as one moves closer to the equator. This is due to the angle of the sun’s rays and the atmosphere's thickness in that region. Near the equator, the sun is more directly overhead, leading to a shorter path through the atmosphere and resulting in less scattering and absorption of UVB radiation. This increased intensity of UVB rays is significant because it plays a key role in vitamin D synthesis in the skin, which is essential for various bodily functions.

Conversely, while UVA rays are present at relatively consistent levels regardless of latitude, vitamin D levels are influenced by UVB exposure, and ozone concentration can vary based on several factors unrelated to proximity to the equator. Therefore, UVB's increased presence near the equator is pivotal for both understanding the effects of sun exposure and the necessity for protective measures against potential overexposure.