Red bloods cells have cell membranes that allow water, oxygen, carbon dioxide and glucose to pass through. all other materials are blocked from entering. this makes the membrane

As soon as possible this assignment is due in 5 minutes atoms in a molecule are bonded together by sharing, gaining, or a. photons b. protons c. neutrons d. energy f. electrons

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

Which of these is not an obstical to the future of space exploration? fundingresearch ideas technologytime