Why do erythrocytes swell and burst when placed in water?
(a) since water concentration is higher outside the cell, water moves inward by passive diffusion.
(b) since hemoglobin concentration is higher inside the cell, hemoglobin moves outward by exocytosis.
(c) since potassium ions are more concentrated inside the cells, potassium ions move outward by osmosis.
(d) erythrocytes pump water inward by active transport to balance osmotic gradients.
(e) water is a universal solvent and simply dissolves the erythrocyte membranes.

Which of these is true of the cytoplasm of an unfertilized egg? a. it is an unevenly distributed mixture of mrna, proteins, organelles, and other substances. b. it does not contain substances that are important in directing development. c. these substances are supplied by the sperm. d. it does not contain substances that are important in directing development. e. development is directed solely by the surrounding cells. f. it is a homogeneous mixture of mrna, proteins, organelles, and other substances. g. it does not contain substances that are important in directing development. h. these substances are produced by the dna of the fertilized zygote.