<human>:  What is the best sunscreen to protect from ultraviolet rays in 2021?
<bot>: The best sunscreen to protect from ultraviolet rays in 2021 is one that has a high SPF (Sun Protection Factor) rating and is water-resistant. Look for a sunscreen that has a rating of at least SPF 30 and is labeled as "broad spectrum" to ensure that it blocks both UVA and UVB rays. Choose a sunscreen that is specially designed for your skin type and that is free of parabens, fragrances, and other potentially irritating ingredients.