Heart is actually suspended into thoracic cavity. Therefore, on running, heart starts vibrating back and forth. And it feels like fast heart beating. doneclear
B)
Legs are the organ responsible for running. Legs are below the heart. Therefore, heart do not require any force to send the blood in the legs. John might have some heart problem, that is why his heart was beating fast. doneclear
C)
Muscles, responsible for running, worked hard while running. Therefore they required great amount of energy. Cells required faster transportation of required materials. Therefore, hearts started to beat fast in order to fast the circulation of blood. doneclear
D)
Actually it is nothing overall. He got tired of running therefore he feels so. doneclear
Loss of greater amount of blood means loss of a number of hemoglobin. Hemoglobin is the carrier of oxygen. Therefore, capacity of carrying oxygen of the blood might have reduced in the body which has ultimately led to death doneclear
B)
Work of transportation is carried by blood. Less amount of blood led disturbance in the transportation work, which causes accumulation of waste substances inside the body and lack of oxygen and food for the cells doneclear
C)
Blood contains WBC. WBC fights against pathogens. Therefore, improper amount of blood means weakening of defense system of the body. doneclear
D)
Volume of the blood vessels is reduced in order to maintain the pressure and flow of the blood doneclear
Our body has not adapted to store the air inside the body as the environment in which we live is full with air. Lung is not used to store air although it provides larger surface area in order to filter respiratory gasses efficiently and effectively doneclear
B)
To meet the emergency situation, body has developed an improved transportation system for fast carrying of respiratory gasses rather than the organ for storage of air. doneclear
C)
Our body has a very improved respiratory system and it does not require any special organ to store the air. doneclear
D)
Like the heart, lung also expands and contracts. And this movement of lung clears that lung in not a store house doneclear