That would be the nervous system.
Answer;
-A teenager teaches her brother how to text (same generation).
Explanation;
-Cultural trait is a characteristic of human action that's acquired by people socially and transmitted via various modes of communication.Culture is the integrated pattern of human knowledge, belief and behavior. Every society has its own particular culture.
-Vertical transmission occurs from parents to offspring and is a function which shows that the probability that parents of specific types give rise to an offspring of their own or of another type. Horizontal transmission is cultural transmission taking place among peers in a given population.
It results in the a narrowing of the arteries which slow blood flow
