Which is the best explanation for why there is a continued need to develop new antibiotics to fight bacterial infections?

Today, drug-resistant infections are a serious threat to people's health. Hundreds of thousands of lives are lost every year because of infections that can no longer be treated with existing drugs. Discovering new antibiotics, able to kill drug-resistant bacteria, is essential to saving modern medicine.

the question isn't complete here so i can't right an answer '_'

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.