Until the twentieth century, sunburnt skin was a sign of poverty, since people with skin likebecause if you had dark skin, it meant that you worked outdoors for a living. Until the twentieth century, sunburnt skin was a sign of poverty, because if you had dark skin, it meant that you worked outdoors for a living.

People with higher income have more possibilitiescan afford to travel more and get a suntan. People with higher income can afford to travel more and get a suntan.

Tawny skin can also be looked attractive and healthy. Tawny skin can also look attractive and healthy.

I didn't know the word tawny before you used it just now. It's correct, and beautiful, but perhaps literary. I would stick with "tan skin" in day-to-day writing.

In reality, tan iss are a response to skin damage of the skin, but, not a sign of health. In reality, tans are a response to skin damage, not a sign of health.

Yours is grammatical, but it sounds quite unnatural to me.

Too much exposure of sun rays may be dangerous or, even worse, lethal. Too much exposure of sun rays may be dangerous or, even worse, lethal.

You could also write "... or even worse—lethal." But this is all style and punctuation, no real problem.

Anyway,But that doesn't implymean we have to hide indoors all summer. But that doesn't mean we have to hide indoors all summer.

And keep in mind to wear sunglasses with aone hundred per cent protection from UV radiation. And keep in mind to wear sunglasses with one hundred per cent protection from UV radiation.

Tawnyn skin can also look attractive and healthy. Tan skin can also look attractive and healthy.

Tawnynned skin can also look attractive and healthy. Tanned skin can also look attractive and healthy.

In reality, However, a suntan areis a response to skin damage, but not a sign of health. However, a suntan is a response to skin damage, not a sign of health.

Too much exposure tof sun rays may be dangerous, or even worse, lethallethal/deadly. Too much exposure to sun rays may be dangerous, or even lethal/deadly.

And keep in mind to wear sunglasses with one hundred per cent protection from UV radiation. And keep in mind to wear sunglasses with one hundred per cent protection from UV radiation.

Combine with the previous sentence.

In reality, tan is a response to skin damage, butand not a sign of health. In reality, tan is a response to skin damage, and not a sign of health.