In the examples below, notice that transportation and park ticket prices stay the same even when the number of days changes. If you're staying somewhere that's relatively inexpensive and not eating out all the time, you can often extend a trip from 4 to 7 days for very little money.
Some seeing eye dogs are selected from breeders specifically because they possess a certain temperament that is required of service dogs. However, many seeing eye dogs are rescued from animal shelters. All dogs who enter the training program to become seeing eye dogs must past a series of rigorous personality tests. If the dog passes the tests, they are then taken to a training facility.
The central retina of the canine eye contains about 20% cones, while humans have an area of 100% cones called the fovea. The cones work best in mid to high levels of light and have the ability to detect color. Humans are believed to have three different cone types, a trichromat, while dogs have two, a dichromat. Each cone contains a photopigment that is maximally sensitive to a separate wavelength of light.