2. ¿Cuál es la longitud de un riel de hierro de 50m a 40°C, si desciende la temperatura a 6°C?. ¿Cuánto se contrajo?​

myth. it was once thought that animals, including cats and dogs, could only see in black and white. however, scientists have proven this to be a myth. in all animals, including humans, the perception of colour is determined by the presence of cells in the eye called cone photoreceptors.