When two dihybrid individuals are mated, this is called a dihybrid cross. Even though the parents of a dihybrid cross have the same genotype and phenotype, their offspring could show any one of 9 different genotypes and 4 different phenotypes. The phenotypic ratio of offspring produced from a dihybrid cross is 9:3:3:1. To unlock this lesson you must be a Study.com Member.
Sounds are heard by the ear as either being loud or soft. The loudness of a sound in measured in decibels. Decibels refer to the energy produced by that sound. A human can hear sounds ranging from 0.1 decibels, which is very soft, to sound which measure 120 decibels. Younger people can often hear lower volumes better than older people.
Noise in our environment can be described by three characteristics -- loudness, pitch, and time variation. Loudness is the intensity of sound or sound energy, and is described in terms of decibels (dB). For example, the louder the sound, the greater the decibel value. Pitch is the note or wavelength of the sound.