Answer:
 A specific environmental factor that will cause a response to living things will be light from the sun.
Explanation:
An enhanced amount of light from Sun will cause the plants to have enhanced photosynthesis. Photosynthesis can be described as a process by which plants use light energy from the sun to convert carbon dioxide and water into sugar (food) and oxygen.
In animals, enhanced amount of light from the sun will cause sweating and vasodilation. 
 The process of photosynthesis won't occur in animals and the process of sweating won't occur in plants.
 
        
             
        
        
        
Unduplicated chromosomes are single chromosomes with a single line strand and one DNA molecule (if that's what you are looking for).
        
                    
             
        
        
        
Normal cells in the body follow an orderly path of growth, division, and death. Programmed cell death is called apoptosis, and when this process breaks down, cancer begins to form.
        
             
        
        
        
Answer: C). Sensory neurons, D).motor neurons
Explanation: Sensory neurons are nerve cells that carry signals from the external parts of the body such as the skin, eyes, ear, nose (the sense organs) to the brain. 
Motor neurons are nerve cells that carry information or messages away from the central nervous system ( brain and spinal cord) to the rest of the body such as the skin, muscles and glands.
 
        
             
        
        
        
The skin acts as a barrier for protecting the body from the harmful things such as sun rays, moisture, cold.
<u>Explanation:</u>
Skin plays an important role in regulating body temperature. It helps to prevent harmful substances enter into our body, and does not allow to loss water in our body. Its form the barrier that prevents harmful substances and microorganisms enter in our body. 
Our skin is the protecting layers and against loss of water and blood from our body. Its help us to maintain the constant body  temperature. The important role of the skin us to protect our body from the ultraviolet rays.