Which of the following statements describe physical properties and which describe chemical properties?
(a) Iron has a tendency to rust.
(b) Rainwater in industrialized regions tends to be acidic.
(c) Hemoglobin molecules have a red color.
(d) When a glass of water is left out in the sun, the water gradually disappears.
(e) Carbon dioxide in air is converted to more complex molecules by plants during photosynthesis.