The scientific method is a systematic process that involves:
Making an observation.
Stating a question.
Formulating a hypothesis.
Conducting an experiment.
Analyzing the data and drawing conclusions.
Oxygen is a non-flammable gas due to the fact that it does not burn. But oxygen is needed for burning to take place; that is, oxygen support combustion. The primary hazard for oxygen is as an oxidizer. As an oxidizer, oxygen vigorously accelerates combustion. Because of this, a minimum of twenty feet must be maintained between oxygen and other combustible material or else, the oxygen container can explode if ignited.
The answer is letter C.
Aerobic activities help the heart to pump blood at an increase rate with each heartbeat. The heart is a muscle, therefore through exercise, these muscles are also developed the same way that the skeletal muscles are. When the heart becomes strong it tends to pump less but with a more forceful action causing blood to instantaneously flow all over the body systems. Aerobic activities that last for 30 minutes are enough to cause the heart to pump extra and get developed into a strong muscle.
