Scientists have found containing fossilized cyanobacteria (blue-green algae). They show that life has been present on the Earth from early ages. Oparin and Haldane were two scientists who hypothesized that life needed reducing environments initially to appear. The ocean in the early ages was (devoid of oxygen) and acidic.

One function of the immune system is to attack the foreign cells to protect the body. in organ translate , the body recongnizes that the new organ is made of foreign cells. wha kind of medicine would you give a patient to increase the chances of transplate success

Which statement describes characteristics of planarians? a they live in oceans, are parasites, and reproduce only sexually. b they live in fresh water, are parasites, and reproduce only asexually. c they live in oceans, are free living, and reproduce sexually and asexually. d they live in fresh water, are free living, and reproduce sexually and asexually.

How far down have geologists drilled holes ? (science) a: 3.8 km b: 12 km c: 100 m d: 1200 km