Which of these is a compound?

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 the following is an example of a tissue on the digestive system a.the stomach b.smooth muscle that lines the stomach c.nerve cells in the stomach d. enzyme molecules in the stomach

Plant species a has a diploid number of 12. plant species b has a diploid number of 16. a new species, c, arises as an allopolyploid from a and b. the diploid number for species c would probably be a) 12. b) 14. c) 16. d) 28. e) 56.