Complex sentence: When the Joey is born it crawls from the vagina to the pouch, the pouch is basically a fold of skin with a single opening that covers the nipples to protect the Joey as it continues to develop.
Split into simpler sentences: When the Joey is born it crawls from the vagina to the pouch. The pouch is basically a fold of skin with a single opening that covers the nipples to protect the Joey as it continues to develop.