Why is this table not normalized?

Question

I am taking a database course, and I am studying table normalization.

Can someone explain to me why the second table in the first row on the right is not normalized?

Answer 1

, , , : 23 CS101 B +
23 B102 C +
, ( ). (, , ).
:
, , , , .

, .
, id, name and DOB , id .
, 1NF, 2NF, 3NF .. , . , .

Answer 2

, . , , .

student_name , students student_id (- , .).

Answer 3

, id, student_name ( ), (, id) . (name) , id.

3NF , ", ", ", Codd"!

.

Answer 4

23 - j.smith

Codd 1