Cervical lymphadenitis is usually caused by a viral upper respiratory infection. The key symptom of lymphadenitis is the presence of a painful mass in the cervical area, often accompanied by fever, runny nose, sore throat, and cough.
Question and answer. Which of the following defines evolution? a change in environmental conditions a change in an animal's physical traits a change in a population's gene pool a change in an individual's genetic. makeup. Evolution is a change in a population's gene pool.
Evolution is the change in frequency of the alleles in a gene pool over time; evolution is when a population of species gets more suited to its environment over time. Evolutioâ¦n occurs with mutations and natural selection. What happens is that in a population of species, not all of them are the same.