I believe it is biosphear<span />
        
             
        
        
        
 Answer;
-Sensation
Sensation is the activation of receptors in the various sense organs 
Explanation;
-Sensation is the activation of sensory receptor cells at the level of the stimulus. Perception is the central processing of sensory stimuli into a meaningful pattern. Perception is dependent on sensation, but not all sensations are perceived. 
-Receptors are the cells or structures that detect sensations. A receptor cell is changed directly by a stimulus. A transmembrane protein receptor is a protein in the cell membrane that mediates a physiological change in a neuron, most often through the opening of ion channels or changes in the cell signaling processes. 
 
        
             
        
        
        
The correct answer is phototrophism.
Phototrophism is said to be the growth of a plant toward a source of light.
It is response to the stimulus of  light and is seen when a plant bends towards the direction that light is coming from. Response by plants to a stimulus is called tropism. The  word or prefix "photo" means or refers to light. Therefore phototropism simply means response to light. 
Phototropism can be especially evident in the jungle where the jungle floor gets very little light. If a tall tree falls to the ground, it leaves a gap in the canopy through which sunlight streams to the ground. Many jungle plants growing on the ground will bend towards the  gap  and rapidly grow towards the source of  light.
 
        
                    
             
        
        
        
Answer: Respiratory system, Excretory system, and Endocrine system.
Explanation:
Homeostasis is the process through which several organ systems work to maintain a stable internal environment in the body. There are three organs of the body which ar eaccurately maintained by homeostasis:
Respiratory system: High carbon dioxide content in the blood triggers faster breathing. Most frequently, the lungs exhale, which quicker extracts carbon dioxide from the body.  
Endocrine system: High blood sugar content causes insulin release by an endocrine gland called pancreas. Insulin is a hormone which helps the cells absorb blood sugar.
Excretory system: A low blood level of water causes kidney accumulation of water. The kidneys contain more concentrated urine, so less water from the body is lost.  
Hence, three critical areas are respiratory system, excretory system, and endocrine system that are accurately maintained by homeostasis.