Answer:
Tongue-rolling is dominant, and both parents were heterozygous
Explanation:
Tongue rolling is a type of variation in human beings. When allelic genes are not identical as in Tt, the condition is referred to as heterozygous. An individual with such a genotypic condition is referred to as a heterozygote.
Both parents had a genotype of Tt and they could roll their tongues because T is dominant over the t gene.
T t
T TT Tt
t Tt tt
TT : Tt : tt
1 : 2 : 1
In a heterozygous parent Tt, the chance of producing T gamete from both parents is each 1/2 each. Similarly the chance of forming t gamete is 1/2. Therefore, the chance of gamete T and t fusing to get genotype Tt is 1/2*1/2=1/4.
The ratios of phenotypes are 3/4 will be able to roll the tongue and 1/4 will not be able to roll the tongue.
The mode of inheritance was monohybrid inheritance since one characteristic like tongue-rolling is controlled by a single pair of hereditary factors contributed by both parents.
Tongue, epiglottis and sublingual/parotid or submaxillary glands (Salivary glands). Hope this is what you were looking for :)
Answer
B: by turning on a battery-powered radio to hear music
