Question

highly reactive substances. these substances can react with a cells dna. uvb waves can also be directly absorbed by a cells dna. both of these processes change the dnas structure, damaging the skin cell. damaged skin cells send signals to other body cells to trigger dna repair. additional blood cells are sent to the dermis, causing skin redness. this redness is commonly known as a sunburn. the damaged skin cells may be repaired, or they may die and peel off the skins surface. damaged skin cells that do not die or get repaired can develop into skin cancer. select the true statements. all skin cells damaged by uv waves will cause skin cancer. the redness of a sunburn is caused by skin cells peeling off. uvb waves can directly and indirectly damage dna. chromophores can produce substances that damage dna.

Explanation:

• The text states that "Damaged skin cells that do not die or get repaired can develop into skin cancer," not all damaged cells will cause skin cancer. So the first statement is false.
• The text says "Additional blood cells are sent to the dermis, causing skin redness. This redness is commonly known as a sunburn," not skin cells peeling off. So the second statement is false.
• The text mentions "These substances can react with a cell's DNA. UVB waves can also be directly absorbed by a cell's DNA. Both of these processes change the DNA's structure". The substances are produced by chromophores (chromophores can produce highly reactive substances that react with DNA - indirect damage; UVB can be directly absorbed by DNA - direct damage). So the third and fourth statements are true.

Answer:

C. UVB waves can directly and indirectly damage DNA.
D. Chromophores can produce substances that damage DNA.