The answer is hydrogen bond between the complementary strands.
I could be wrong I’m not very smart but I think it’s b
The correct answer is d. "Regeneration" means "forming new cells," and signifies that the disease-causing bacteria cells are multiplying. When there are more of these cells, there is a higher chance for antibiotic resistance (making it take longer for the antibiotics to work). Once there is a smaller concentration of these bacterial cells, the antibiotics become more effective.