Answer:
The correct answer is: <em>C. Increased average lifespan to 78 in the US.</em>
Explanation:
Science has impacted human health by increasing the average lifespan to 78 in the US. Over the last couple of decades, the life expectancy of Americans has increased significantly than what it was 200 years ago. This can be attributed to:
1. Vaccinations- Since the invention of vaccinations, diseases such as tuberculosis, cholera and polio which were major causes of death 200 years ago have virtually been eradicated in the US. 
2. Abundant and safer foods available- Commercial and large scale farming has made a wide variety of nutritious foods easier to obtain.
3. Improved sanitation- Safer drinking water, sewage treatment and stricter food inspection has significantly reduced the rate of illnesses due to poor hygiene and sanitation.  
In these ways, science has impacted human health by increasing the average lifespan to 78 in the US.
 
        
             
        
        
        
Explanation:
Cellulose, hemicellulose and lignin form structures called microfibrils, which are organized into macrofibrils that mediate structural stability in the plant cell wall.
The most important biological role of hemicelluloses is their contribution to strengthening the cell wall by interaction with cellulose and, in some walls, with lignin.
 
        
             
        
        
        
A is your answer. When only one parent produces the offspring, they are essentially cloning themselves, and it is called asexual reproduction. The offspring only have the genes of the one parent. A lack of genetic diversity is one of the drawbacks to asexual reproduction.