Answer:
The Thymus is a unique gland which protects the body against autoimmunity when the immune system act against itself.Hence the Thymus plays a significant role the dual systems i.e.,the lymphatic system (body’s defensive mechanism) and the endocrine system
Explanation:
The Thymus is special gland located anteriorly to the chest directly behind the sternum and in between the lungs. Active until puberty and gradually shrinks to become fat after puberty.
Function: Prior to birth and during childhood thymus engage in producing and maturation of T-lymphocytes or T-cells a particular type of white blood cells which defence the body against infectious disease germs.Though the organ does not function throughout the life span but it plays a significant role protecting the body against autoimmunity refers to an immune system works against itself .Therefore the thymus plays a key role in lymphatic system and an endocrine system.
Secretion:Thymus secretes Thymosin a hormone it instigates the development of T-Cells ( disease resisting cells) Thymosin stimulates the development of T-Cells until a human attains its puberty.
At the age of 75 thymus becomes a fatty tissue.
 
        
             
        
        
        
A molecule is a group of two or more atoms held together by chemical bonds. A compound is a substance which is formed by two or more different types of elements which are united chemically in a fixed proportion. All molecules are not compounds. All compounds are molecules.
        
                    
             
        
        
        
Answer: Systolic pressure.
Explanation:
Every time the heart beats, it pumps blood into the arteries, which are vessels through which blood circulates from your heart to your tissues with the oxygen and nutrients they need. Blood pressure is the force of the blood pushing against the walls of the arteries, and is highest when the heart beats, pumping blood, which is measured as systolic pressure (i.e., when the heart contracts). On the other hand, diastolic blood pressure refers to the pressure of blood in the artery when the heart relaxes between beats (i.e., when the heart relaxes). Since there are two types of pressures, blood pressure readings are given in two numbers, with the top number being the systolic pressure and the bottom number being the diastolic pressure.  
For example, if the systolic pressure measured in a person is 125 millimeters of mercury (mm Hg) and the diastolic pressure is 85 mm Hg, the blood pressure is recorded as 125/85.  
So, <u>the systolic blood pressure is registered with the stethoscope when the cuff is deflated.</u> When two heartbeats are heard, the pressure gauge reading is recorded. <u>When the heartbeat ceases, the cuff pressure is released and the diastolic pressure is measured at this time.</u>
 
        
             
        
        
        
A glucose molecule is  a monomer of starch and cellulose
 
        
                    
             
        
        
        
Answer:
Due to environmental conditions.
Explanation:
With the passage of time, environmental conditions change which causes the evolution of of four legged land animals from fish like creature. This change occurs due to change in environment. In water, there is no need for legs because fish moves with the help of fins and tail but the organisms that lives on land has legs in order to move from one place to another so we can say that change in the physical structure of organism occurs due to environment.