Question

use the text to compare and contrast uva rays and uvb rays.
two kinds of radiation make up the light from the sun that penetrates the atmosphere and reaches earth: long wave ultraviolet a (uva) and short wave ultraviolet b (uvb). though uvb rays tend to damage the skins outer layers, causing redness and sunburn, uva rays penetrate the skins thickest layer, known as the dermis. it was once thought that only uvb rays were cause for concern. over the years, however, scientists have learned that more about how uva rays damage skin cells in the basal layer, where a majority of skin cancers form. now we know that uva rays pose dangers similar to those from uvb rays in terms of skin cancer development. in addition, both types of rays contribute to the premature aging of skin.

Explanation:

• Penetrate the atmosphere: The text states that both UVA and UVB rays penetrate the atmosphere as they are part of the sun's light reaching Earth.
• Penetrate the dermis: The text clearly mentions that UVA rays penetrate the dermis (the skin's thickest layer), while UVB rays damage the outer layers.
• Play a role in skin cancers: The text says that now we know UVA rays pose dangers similar to UVB rays in terms of skin cancer development.
• Play a role in skin aging: The text indicates that both types of rays contribute to premature skin aging.

Answer:

	UVA rays	UVB rays
Penetrate the dermis	$\square$ (Yes)	$\square$ (No)
Play a role in skin cancers	$\square$ (Yes)	$\square$ (Yes)
Play a role in skin aging	$\square$ (Yes)	$\square$ (Yes)