Uracil is the nitrogenous base that is found in RNA but not present in DNA.
Cytosine (C) and thymine (T) are the smaller pyrimidines. RNA also contains four different bases. Three of these are the same as in DNA: adenine, guanine, and cytosine. RNA contains uracil (U) instead of thymine (T).
If we start o war people will die and the population will decrease. If we pollute the air and water there will be less to drink and eat and there will be more floods. This will cause the population to decrease because there will be more deaths.