when brown iodine is exposed to starch it turns dark purple. in an experiment, you placed a cornstarch solution in a small plast
ic bag. next, you placed the bag in a beaker of water containing 10 drops of iodine. if the solution in the plastic bag turned dark purple (select all that apply)
This especially happens with granitic rocks as they were cooling, like at Yosemite National Park. Freeze-thaw: When water freezes, it expands. If moisture seeps into cracks before winter, it can then freeze, driving the rocks apart.
