A scientist was studying a tissue sample. Most of the cells that she examined had a certain amount of chromosome material, but there were also some cells with half as much chromosome material as the others. What is the best explanation for what she saw?

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 example best describes a reflex action? a. eating food when hungry b. coughing when the throat is irritated c. bending down to lift a heavy object d. going for a walk outside

What is the meaning of endocytosis ?