<span>A tiger looks so much different as an adult than it did as a single fertilized egg because it developed through different stages from being a zygote (fertilized egg), to becoming an embryo (where it experiences intense cellular changes), to becoming a fetus (where it gains a great measure of cell specialization, and develops distinct tissues and organ systems). After birth, the tiger still undergoes further growth and development into adulthood. This is largely regulated by the expression of different genes at different times and also by environmental factors.</span>
        
                    
             
        
        
        
Answer:
The correct answer will be option-C.
Explanation:
Hypothalamus is a part of the brain which controls many important functions of the body by producing hormones.
When the amount of water gets reduced in the blood, it leads to a change in the osmolarity which can be easily detected by the osmorecpetors present in the neurons of the hypothalamus.
In response, neurons secrete Anti-diuretic hormone in the blood which acts in the tubules of the kidney where they help in re-absorption of the water from the body.
Thus, Option-C is the correct answer.
 
        
             
        
        
        
They are considered organic molecules because the monomer which make proteins are amino acids which are organic compounds.
        
                    
             
        
        
        
Answer:
Because of the difference in surface area to volume ratio 
Explanation:
Surface are to volume ratio is the area of an object that is exposed to the external environment (surface area), compared to the amount within an object (volume).
Therefore an elephant has a lower surface area to volume ratio than a mouse.
The smaller an object is the greater its surface area to volume ratio.
Small animals have much more surface area per mass than large animals. With so much surface area, they lose heat very quickly. So, a mouse, with a lot of surface area per mass, must spend a lot more energy to stay warm than a large animal.
 
        
                    
             
        
        
        
When cells communicate by the signaling process, one cell produces a signaling molecule that must be received by the signal receptor on or in the responding cell. Signaling molecules are often called ligands, a general term for molecules that bind specifically to other molecules (such as receptors).