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 gradual genetic change of living organisms over time due to ecological pressures they experience. Individuals in an interbreeding population share in a common gene pool. A populationâs gene pool evolves, not an individual, due to changes occurring in such a gene pool. Evolution can occur in several different ways: (1) gene frequencies may be changed by migration, gene flow from another population.