Why was a common language important to Muslim scientists

Do you mean what? If yes, then its arabic.

both believe in many god or polytheism

both built temples that they worshiped in both civilization's god were humanoid

both groups made religion a large portion of their lives

both believe in one religion throughout

the dead were buried with items for the afterlife

the following best describes postwar era writers in their works:

many writers,authors,novelists,poets concentrated more on social art and social writing and stayed away from political writings.