Following the period of the crusades
a) christian invaders adopted muslim scientific learning and military techniques.
b) christian invaders destroyed most evidence of muslim intellectual achievements.
c) muslim defenders repeatedly lost major portions of their empire to the christians.
d) muslim defenders adopted christian military practices in order to defeat their foes.

D.

Explanation:

After the Crusades tons of Muslim defenders took in Christian military practices to more easily defeat their foes. The Christians did not adopt Muslim learning at all, and the Christian invaders also did not destroy any evidence. The Muslims did not lose portions of their empire at all, they prevailed.

if you could provide the poem below, i'd be happy to you!

explanation:

you didn't give us the poem, or the title of the poem. but it is essential for you to give us that, otherwise we can not detect when the poem has a tonal shift!