List the names of gymnasts in ascending order by their heights.
SELECT T2.Name FROM gymnast AS T1 JOIN people AS T2 ON T1.Gymnast_ID  =  T2.People_ID ORDER BY T2.Height ASC
names of gymnasts refers to T2.Name; ascending order by their heights refers to ORDER BY T2.Height ASC; gymnast information is spread across two tables (gymnast and people) and requires a JOIN on Gymnast_ID and People_ID to correlate the data.