The environment includes abiotic (nonliving) and biotic (living) factors. An ecosystem consists of all the biotic and abiotic factors in an area and their interactions
The answer is D. Lymphatic
Skin isn't included in the lymphatic system.
Unlike the hippo's ancestor, whale ancestors moved to the sea and evolved into swimming creatures over a period of about 8 million years. Fossils of gigantic ancient whales called Basilosaurus were first mistaken for dinasaur fossils but were later recognised as mammals.
1/2 of a radioactive substance will remain after 3 half lives.
