You have been advised to check your pulse during exercise in order to monitor your heart rate.what is happening in your heart as your pulse is produced?

Its it contracting allowing a pulse to be created as you work out. The lub dub sound of your heart is basically your pulse. As the heart contracts faster as you work out due to you exerting yourself to an intense workout. 

The author understands the feelings of a mother. When Enrique was a child his mother Lourdes decided to leave children and move to the north of the United States. She wanted to support her family and do something for them.  Enrique’s Journey by Sonia Nazario is a nonfictional piece of literature. When he was 16, he went out to find his mother with nothing but a phone number, to begin with.  He was heartbroken; Meanwhile in Antoine De Saint-Exupèry’s story called the Little Prince,  a plane crashes and the pilot meets a prince of an asteroid.  Both Enrique and the pilot both learn how not to be careless and survive in harsh conditions.