What is Race? What is Racism?

The film Race: The Power of an Illusion episode 1 (attached) notes several common false assumptions about race. These include:

1- Racial categories represent scientifically definable biological differences between groups.
2- Every human has a specific and objectively correct racial identity.
3- Individuals cannot change their racial identity.
4- Every ethnic group has a specific and objectively correct racial identity. (e.g. Irish people are White).
5- Ethnic groups cannot change their racial identity.
6- Because racial identity includes both physical appearance and other, deeper, genetic qualities, a persons race can provide meaningful information about other aspects of their personality, such as athletic ability, musical aptitude or intelligence.

Please choose one of these misconceptions and address the following questions about it in a 250 500 word post.

1- Why is this belief incorrect?

2- How, in your opinion, might this misconception affect peoples experience? In other words, how might this idea about race cause people to see the world differently from how they otherwise might? You may be as specific or general as you want in the way you address this question.