Alice wants to see if she can enhance percent fertilization in her sea urchin experiment. She hypothesizes that depleting Calciu
m (Ca2+) from the sea water will increase percent fertilization. Alice begins by isolating the eggs from the female in salt water (SW) and Calcium-free salt water (CFSW) and then washes the eggs three times in SW or CFSW, respectively. She sees that she has more eggs in her SW group. After doing this, she isolates sperm from the males, dilutes the sperm into equal aliquots and adds a drop of sperm into each of her egg samples. Assume that all sperm and eggs were stored under the same conditions. After an hour, under the microscope she observes that her SW eggs has a higher percent fertilization compared to her CFSW eggs. This contradicts her hypothesis. 1a. What confounding variables could account for error in Alice’s experiment? (Choose three
