Which of the following examples demonstrates poor cohesion?

1.
"First, I'll discuss the benefits of jogging. Formally, I'll explain how it improves mental health."

2.
"Jogging has numerous benefits. Additionally, it plays a crucial role in improving mental health."

3.
"There are many benefits to exercise. In addition, it improves mental health."

4.
"I'll discuss the benefits of jogging first. Also, I'll explain how it improves mental health."

5.
"First, I'll discuss the benefits of jogging. Next, I'll explain how it improves mental health."

The example that demonstrates poor cohesion is 4. "I'll discuss the benefits of jogging first. Also, I'll explain how it improves mental health."

The example that demonstrates poor cohesion is:

3.
"There are many benefits to exercise. In addition, it improves mental health."

This example lacks clear connection and cohesion between the ideas. The phrase "in addition" does not effectively connect the two sentences, resulting in poor cohesion.