The materials and fluid dynamics experiments include the development of new materials using microgravity, and the observation of various phenomena that occur to materials removed from the pull of gravity. Space also allows the verification of various principles of physics and chemistry that cannot be accurately measured while in the Earth's gravitational influence. Experiments in space suggest that vegetable cells divide normally under microgravity, and the formation of roots, stem and leaves is normal. So it seems that the cultivation of plants in space is quite feasible. But although the germination of seeds grown under microgravity appears the same in space as on Earth, there is no geotropic response, so growth is not straight but in various directions.
Studies continue into the mechanism of plants' gravity sense.
And even if oxygen could somehow be supplied to the blood, then if the pressure is below 48 mm of mercury at body temperature the blood will start to boil, so life cannot be sustained. There is also a big difference in the radiation environment. The Earth's surrounding atmosphere protects life on the surface from incoming cosmic radiation, but such radiation is plentiful in space. If it penetrates the cells of living things it can sever DNA chains or its high energy can damage the cell structure. Minor DNA damage can be repaired, but if the cell itself is destroyed nothing can be done.