Life Processes Test - 91

A. Correct option –  D

B. Explanation for correct option – 

Double circulation means when the blood passes through the heart twice - E.g. Birds and mammals( including humans). 

Fishes have heart with two chambers and the circulation is unidirectional and closed circulatory system . 

Hence option D is correct

• The principal excretory organs of our body are the kidneys which maintain the chemical composition of the blood. 
• The kidneys are responsible for maintaining the chemical composition of the blood by the removal and absorption of the various salts, amino acids, glucose, and ions. 
• Thus, the kidney is known as the master chemist of our body.
  

• Peristaltic movement occurs along the esophagus that helps in the movement of food in the digestive tract. 
• There are around 150,000 to 450,000 platelets in the blood. These are involved in the formation of blood clots. 
• Rings of cartilage are present in the trachea. This prevents the airway from collapsing during pressure changes of breathing.

• During systole, because of heart contraction blood is pumped into arteries.
•  Blood pressure is highest as it leaves the heart through the aorta and gradually decreases as it enters smaller and smaller blood vessels (arteries, arterioles, and capillaries). 
• While during atrial diastole, both atria are relaxing, dilating and filling. 
• Blood pressure drops to the lowest level during this state. 

• The brain forms only 2% of the body but uses up to 20% of the Oxygen. 
• It is given  top priority during the distribution of Oxygen-rich blood. 
• The internal carotid arteries and vertebral arteries carry Oxygen-rich blood from the heart to the brain.