Answer:Wildebeest are considered keystone species because their presence has myriad effects on the ecosystem, unlike those of any other species. Wildebeest are the "lawnmowers" of the Serengeti grassland. They keep grass short which in turn reduces the frequency of fires.
 
        
             
        
        
        
Moistens tissues especially those that belong to the eye, the nose and mouth.
Water in the body also regulates body temperature.
It transports oxygen and nutrients to the cells.
It also helps to prevent constipation.
        
             
        
        
        
<span> RNA was thought of as little more than a messenger between DNA and proteins, carrying instructions as messenger RNA (mRNA) to build proteins. However, RNA can do far more. It can drive chemical reactions, like proteins, and carries genetic information, like DNA. And because RNA can do both these jobs, most scientists think life as we know it began in an RNA world, without DNA and proteins.</span>
        
             
        
        
        
Whole genes and parts of genes can be extracted from chromosomes, linked to other DNA molecules to form recombinant DNA and introduced into living cells. In a process known as gene cloning, the host cell's biochemical processes are used to make many copies of the inserted gene and the protein it codes for.