Based on the clue 'cast thy blank upon the waters for thou shalt find...', what is the answer?

Based on the clue 'cast in the role of the fourth most abundant eleme...', what is the answer? Based on the clue 'cast iron which is cast in a mold antedates this t...', what is the answer? Based on the clue 'cast member nora dunn boycotted the final show of ...', what is the answer? Based on the clue 'cast members mike farrell david ogden stiers both...', what is the answer? Based on the clue 'caste of priests after whom the third book of the ...', what is the answer? Based on the clue 'castilian is the official standard form of this ro...', what is the answer? Based on the clue 'castillo de san marcos in this florida city is the...', what is the answer? Based on the clue 'castillo interior is a classic spiritual work by t...', what is the answer?