How many chromosomes do humans have in each cell? A. 46 pairs, total of 92
B. 10 pairs, total of 20
C. 22 pairs, total of 44
D. 23 pairs, total of 46

Which of the following statements is true of enzymes? a)they dont provide an active site for substrates to bind in a reaction b)they act on a specific type of substrate in a reaction c)they unusable after a reaction d)they change shape after a reaction

Milk production during breastfeeding is increased by the suckling of a newborn from his mother's nipple. this type of feedback mechanism best describes a positive or negative

Two students are working together on an experiment that measures the effect of different liquid fertilizers on the thickness of plants’ stems. which is most likely to result in the greatest amount of error in their scientific experiment? a.one student measures the plant stem widths by using calipers. the other student measures the widths of the same plant stems again by using a different pair of calipers. b.one student measures the plant stem widths by using calipers. the other student types the measurements as they are taken into a computer spreadsheet. c.one student weighs liquids for the experiment by using a calibrated scale. the other student weighs liquids for the experiment by using a different calibrated scale.