During which one of the following exercise intensity levels would you still be able to sing

The exercises which use low heartbeat are the one in which a person can sing. The example of these exercises are normal walk, yoga, etc.

Explanation:

Exercises are essential for human body to keep the body fit. These exercises use all the body parts and during performing this exercise the heart beat becomes very high. Due to this reason a person cannot speak. But there are various forms of exercises in which the rate of heartbeat remains slow. And during these exercises a person can easily sing or speak.

For a person to remain fit all types of exercises are necessary. Therefore, we can see that low intensity exercises can make a person to sing or speak.

answer: when you start thinking negitivly and start having suicidal thoughts

or harming yourself, sadness is part of depression as well as fear and anger combined

it may have problems procreating.