The deciduous dentition or baby teeth refer to the first set of teeth human have before the permanent teeth, these teeth are prevalent during infancy and include 20 teeth: 4 central incisors, 4 lateral incisors, 4 canines and 8 molars divided into 4 primary molars and 4 secondary ones. In the case of premolars, these are part of permanent teeth but not of deciduous teeth as they only appear after deciduous teeth begin being replaced and these replace the molars in deciduous dentition. Thus, the number of premolars in deciduous dentition in humans is 0.
The climate of a region is determined through the observation of weather patterns over a long time- usually at least 15 years- in a region. Studying climate change would therefore also take very long time as meteorologists attempt to perceive changes in these weather patterns. In this case 30 years can be enough to notice a significant increase in rainfall patterns which can be classified as climate change.