About 10,000 years ago, around the time of the last ice age, Cheetahs nearly became extinct. Recent efforts have helped them recover, but cheetahs alive today have nearly identical DNA. This is a result of:

Tuberculosis is a disease caused by a bacterium and can often be fatal. for several decade , antibioticre very succesful in killing tuberculosis bacteria but now strains of the bacteria have developed that can only killed by when treated for long period of time with multiple types of antibiotics. why have the antibiotics become less effective aagainst tuberculosis