14. Which of the following is true of the nucleus? (a) The nucleus is considered the control center of the cell.

(b) The nucleus contains all the cell’s DNA.

(c) All cells have a nucleus.

(d) all of the above

Which real-world scenarios below represent physical and chemical changes? -running a car -exploding fireworks -mixing water and powdered drink mix -combining oil and vinegar to make salad dressing -taking aspirin for a headache -diluting bleach with water-digesting dinner-spreading peanut butter on bread

Which type of substance ionizes partially and gives off hydrogen ions when dissolved in water? a. strong acid b. strong base c. weak acid d. weak base

What are the major types of a chemical compound