Which of the following are included in the immune system?

Assertion $A$: Innate immunity consists of various barriers. Reason $R$: Exposure to a pathogen is required for the stimulation of innate immunity. Which option is correct for Assertion $A$ and Reason $R$?

Anamnestic immune response is $ - $

Which of the following are included as cellular barriers in innate immunity?

Select the option that contains only secondary lymphoid organs.

Person '$A$' cannot step out of his house. He has to spend his entire life in sterile isolation; otherwise, he would quickly contract a fatal infection. This person has almost no effective immune system. This disease is also called '$baby$ $in$ $a$ $bubble$ $syndrome$'. Identify the disease this person '$A$' is suffering from.