Question

which describes a mendelian trait?A. Humans have either attached earlobes or detached earlobes. B.Human body mass is controlled by many genes. C. Blood type in humans has several diffrent alleles. D. Plants can grow to wide range of hieghts.

Answer 1

A. Humans have either attached earlobes or detached earlobes.

"Mendelian Traits are those traits which follow Mendel's rules of only 2 possible versions of a gene (1 dominant, 1 recessive)."
https://www.nlm.nih.gov/exhibition/harrypottersworld/pdf/mendeliantraits.pdf

Answer 2

Answer:

Option A.

Explanation:

Mendelian trait follows the rule of "law of dominance". According to this law,"In a pair of contrasting trait, the one allele may express itself and hides  the expression of other allele. The allele that can express itself is dominant allele and the allele that cannot express itself in heterozygous condition is recessive allele".

Detached earlobes allele is dominant over attached earlobe allele. The allele of detached earlobes can express itself in heterozygous condition whereas attached earlobes express itself when present in homozygous condition. Thus, the attached and detached earlobes follows the Mendelian trait.

Hence, the correct answer is option A.