Final answer:
In the snail Cepaea nemoralis, the type of chromosome that is autosomal is option 3) Autosome. Autosomes are chromosomes that are not involved in sex determination and are the same in both males and females. Homologous chromosomes can include both autosomes and sex chromosomes but are not the same as autosomes.
Step-by-step explanation:
The chromosome type referred to as an autosome is a non-sex chromosome; it is not directly involved in determining the sex of an organism. In humans and many other species that use the XY sex-determination system, the sex chromosomes are the X and Y chromosomes, where typically males have one X and one Y chromosome (XY) and females have two X chromosomes (XX). Autosomes are the remaining chromosomes that do not determine sex and are the same in both males and females. Therefore, in the context of Cepaea nemoralis, which is a snail, the autosomal chromosomes are those that are not involved in sex determination.
To respond to the student's question regarding the type of chromosome that is autosomal in the snail Cepaea nemoralis, the correct answer would be option 3) Autosome. Sex chromosomes, heterochromosomes, and homologous chromosomes are all different concepts. Homologous chromosomes refer to a pair of chromosomes that have the same structure and gene sequence, which can include both autosomes and sex chromosomes. The great majority of human genes are located on autosomes, as is likely the case in Cepaea nemoralis as well.