Researchers looking for fossils of the earliest life forms face many hurdles. For example, few sedimentary rocks date back more than 3 billion years. Review what you learned about plate tectonics (Section 16.5). Explain why so few remaining samples of these early rocks remain.

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 !         : )

it's c.us forest service