Cultural traits are transmitted horizontally and vertically through learning. Which of the examples below shows the horizontal transmission of culture?

A. A mother teaches her son how to ride a
bike.
B. A female chimpanzee teaches her
offspring to capture termites using a stick.
C. A son inherits the recessive form of a gene
from his father.
D. A teenager teaches her brother how to
text.
E. None of a-d are examples of horizontal
transmission of culture.

answer:

D. A teenager teaches her brother how to
text.