The terrestrial gastropods are the only mollusks that have adapted to all the habitats of the Earth. They dwell in areas of high altitude, mountainous regions, hot and cold places. Land snails live and perform their vital functions on the ground and not in the sea or bodies of fresh water.
I believe that the areas are tropical and polar zones.
0:3:1
Explanation:
Tasters have the dominant allele for the itter taste of PTC, they can be homozygous TT and heterozygous Tt.
Non-tasters are supposed as autosomal recessive characters
they are homozygous recessive tt when expressed
Given in the equation two heterozygotes parents would produce offspring with the trait in the following ratio.
Tt (parent 1)
Tt (parent 2)
If a punnet square is made
T t
T TT Tt
t Tt tt
The phenotypic character is in the ratio of 0:3:1
There will be 25% chances of recessive trait of non-tasters in the progeny of heterozygous parents.