The true statements about Islamic scholars who made significant contributions to major scientific ideas and technological advances are:
- They knew that Earth was round.
- They set up an observatory at Baghdad to study the position of the stars.
The other statements about inventing papermaking (which actually originated in China) and the belief that Earth was flat are not true in the context provided. Islamic scholars were aware of the roundness of the Earth, and they did contribute significantly to astronomy and the study of stars at observatories like the one in Baghdad.