Based on the clue 'a squirting shower head may be clogged with this ...', what is the answer?

Based on the clue 'a squash or pumpkin or pierced by a bulls horn', what is the answer? Based on the clue 'a squash thats been pierced by a bulls horn', what is the answer? Based on the clue 'a squeeze of these snakes the reticulated ones of ...', what is the answer? Based on the clue 'a squirrel uses this fluffy appendage for balance ...', what is the answer? Based on the clue 'a st helena california museum displays the toy sol...', what is the answer? Based on the clue 'a st valentines church in italy was built over one...', what is the answer? Based on the clue 'a stable owner who always rented out the horse nea...', what is the answer? What is associated with: a stadium with the worlds largest roof was built in 1972 for the olympic games in this city?