Answer:
A) There is a change in the environment: an antibiotic is added. Some of the bacteria adapt to the new environment. They survive and reproduce.
Explanation:
I. Variation: Different organisms manifest different appearances and behaviors. It depends whether it's a body size, hair color, certain marks on one's face, tone of the voice, number of offspring. Some attributes are the same in every individual: for example, everybody has two eyes, one mouth, one nose, etc.
II. Inheritance: Certain attributes are passed from a parent to an offspring. They are passed heritably, while some other attributes are very environmentally oriented and have nothing to do with inheritance, but the adapting to the environment.
In this phase, certain species produce more offspring and they are fighting for their survival. Due to that, major environmental changes occur as they produce more and more each time, which leads to struggling for resources, and it's further passed to the next generations.
III. Selection -- it's manifesting by the scheme where organisms who are better at adapting to the environmental changes have a bigger chance to mature. When they do, they reproduce and pass all the qualities to their offspring. Therefor, bacteria that is better at adapting to the new environmental changes, is more likely to survive and reproduce and it goes on like that in circles.
IV Population is growing bigger and bigger and as a result we have an evolution.