Oxygen carried in a hemoglobin molecule is bound to a/an           a. calcium atom.    b. globulin molecule.    c. iron atom.    d. protein molecule.

As the human population grows, what happens to our natural-resource requirements? o they increase o they decrease o they do not change. they go in cycles

Diego conducted an experiment to find out what kind of ball bounces the highest when dropped from a five-foot platform. he used a golf ball, a tennis ball, and a soccer ball. he dropped each ball from the balcony once. diego recorded his observations after each drop. what can diego do to best improve the reliability of his results? a) drop each ball from the platform three more times b) record his observations in more than one unit c) write at least two scientific questions after the experiment is complete d) share his results with other people who have done similar experiments you for the !

Acell in the human nervous system whose primary function is to form myelin and the blood-brain barrier, respond to injury, remove debris, and enhance learning and memory is called a(n) cell.