1. Not openly displayed, hidden, or not shown. 2. Come together, or moving towards union. 3. The art of speaking or writing effectively.

28. evolution

29. environment, survive, offspring  

explanation:

the answer is mosques. they are an important part of islamic culture.

there is no correct list among the choices you've provided.

the list might look something like this:

-- baby human

-- piccolo

-- flute

-- soprano singer

-- trumpet

-- tenor singer

-- trombone

-- baritone singer

-- baritone horn

-- bass singer

-- tuba

since i had to make up the list myself, i made it easy on myself, and i didn't try to shuffle the string instruments and woodwinds into it too.