It was the advent of microscopy that opened up an understanding of the building blocks that constituted living tissues.
ɪt wʌzðɪ ˈædvɛnt ʌv mˈaɪkɹəskəpi ðæt ˈoʊpənd ˌʌp ɐn ˌʌndɚstˈændɪŋ ʌvðə bˈɪldɪŋ blˈɑːks ðæt kˈɑːnstɪtˌuːɾᵻd lˈɪvɪŋ tˈɪʃuːz.