the upper thigh is proximal to the hip when compared to the knee -- this means that the upper thigh is located in a manner that it is nearer to the centre of the body or attachment, in this case, hip. It's the same for hip and knee, they are located in a certain way that their distance is the same. Upper thigh is inferior to the hip -- it is inferior to the hip because it's down from the hip. For example, rib would be superior to the hip, because it's higher compared to it.
Leaving food out at room temperature encourages bacteria to thrive, which is why it's important to put leftovers in the fridge after a maximum of 2 hours after being cooked.