Which is a primary lymphoid organ

Which is the primary lymphoid organs of birds?Mention its location and role.

Which of the following is a primary lymphoid organ ?

Which of the following is a primary lymphoid organ ?

Primary lymphoid organs are

Primary lymphoid organ is -

Primary lymphoid organs are

The primary lymphoid organ in

The primary lymphoid organ is

Assertion (A): spleen is a primary lymphoid organ Reason (R ):Primary lymphoid organs trap antigen and destroy them.