The drastic decline in sea urchin populations in the Caribbean reef systems allowed algae to overgrow corals, resulting in depredation of the coral reef systems. When urchin populations rebounded, the coral population did not fully return. The Caribbean reef systems exhibited

thymine. in rna, thymine is replace by uracil

answer >   yes we do, women; have three holes, urethral opening(pee hole, vagina, and the women pee/girls pee out of the urethra like the men do; only they have a single opening to pee/ejaculate.   (sorry if i'm too forward with this, but this is for a biology class, isn't it? )

hope that !         : )