Why do identical twins have different fingerprints?
Although identical twins share the same DNA, they don't look identical cell-for-cell, because not every aspect of your physical appearance is rigidly determined by your genes. Fingerprints are formed semi-randomly as the foetus develops in the womb andare affected by such things as chance fluctuations of hormone levels. Similarly, the pattern of freckles and moles on the skin is caused by random mutations and will vary between identical twins.
Why do fingers and toes wrinkle when left in water?
The waterproof coating on our skin gets rubbed away from areas of our bodies like our hands and feet that are frequently in contact with objects. If you immerse yourself in water with a lower concentration of dissolved salts than that of your cell contents, water will be absorbed by osmosis and cause your skin cells to swell. Since they are anchored to the tissues below, they are forced to corrugate to accommodate this.
Why can't we just fill in the ozone hole with man-made ozone?
The sheer scale of the notorious hole - or, more accurately, depleted region - in the Earth's ozone layer over the Antarctic beggars belief. At its peak each September, it spans an area bigger than the continental United States, and tens of millions of tonnes of ozone would be needed to fill it up again. Simply creating that amount of ozone, let alone getting it where it's needed, would be astronomically expensive.