Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE prereq ( course_id text, prereq_id text )
TABLE: CREATE TABLE time_slot ( time_slot_id text, day text, start_hr number, start_min number, end_hr number, end_min number )
TABLE: CREATE TABLE section ( course_id text, sec_id text, semester text, year number, building text, room_number text, time_slot_id text )
TABLE: CREATE TABLE teaches ( id text, course_id text, sec_id text, semester text, year number )
TABLE: CREATE TABLE instructor ( id text, name text, dept_name text, salary number )
TABLE: CREATE TABLE student ( id text, name text, dept_name text, tot_cred number )
TABLE: CREATE TABLE advisor ( s_id text, i_id text )
TABLE: CREATE TABLE classroom ( building text, room_number text, capacity number )
TABLE: CREATE TABLE course ( course_id text, title text, dept_name text, credits number )
TABLE: CREATE TABLE takes ( id text, course_id text, sec_id text, semester text, year number, grade text )
TABLE: CREATE TABLE department ( dept_name text, building text, budget number )

### Question ###
What is the title of the course that is a prerequisite for Mobile Computing?

### Accurate SQL ###

SELECT title FROM course WHERE course_id IN (SELECT T1.prereq_id FROM prereq AS T1 JOIN course AS T2 ON T1.course_id = T2.course_id WHERE T2.title = 'Mobile Computing')