Answer:
Placebo, Is used to describe a substance given in clinical trial that does not contain the drug.
Explanation:
- Clinical trials are done to evaluate the effectiveness of a drug in treating a particular medical symptom or disease.
- In such case a placebo is used as a control in the experiment.
- A placebo contains all the components as the medicine except for the drug that is being tested.
- A placebo is given to one group of patients having the symptoms for which the drug is tested while another group of patients with same symptoms are given the drug.
- If the group that was given the drug show symptoms of cure  while the group that was given placebo does not show changes. Then the drug is said to be effective.
 
        
             
        
        
        
C i think . Hope this helps
        
                    
             
        
        
        
Answer:
Carbon.
Explanation:  It is the only element that makes up every living thing.
 
        
                    
             
        
        
        
At the West African Institute for Trypanosomiasis Research Field Station at Ugbobigha was 21·5 per cent.; this species is believed to be of major economic importance because its presence must prevent the keeping of cattle in large areas of potential grazing.
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Trypanosomiasis, both of humans and of livestock, is one of the most important factors restricting economic development in Africa today. The present paper outlines how this disease is limiting agricultural, veterinary and forestry development in the Sudan, Bechuanaland and West Africa.
The present tsetse-fly distribution is reviewed. Glossina palpalis and G. morsitans occur in the south Sudan and G. morsitans in the Ngamiland district of Bechuanaland; G. morsitans, G. palpalis and G. tachinoides are the most important species in West Africa.
These tsetse flies have altered the cattle distribution in all three regions and, in addition to causing widespread disease, have created local overstocking problems in the tsetse-free grazing areas, and have enforced nomadism on breeding herds and economic loss in slaughter cattle along the trade cattle routes in West Africa.
Human trypanosomiasis is not now such an urgent problem and public health measures have led to its control in all three areas.
Increased agricultural development, which can be a successful and economic method of reclaiming land from tsetse flies, must be intensified in all three areas.
Forest conservation policy comes into conflict with tsetse control measures only in West Africa.
Detailed tsetse-fly surveys and research, on which future plans can be firmly based, are now urgently required.
        
             
        
        
        
<span>Made mostly of collagen. Its also a living growing tissue.</span>