The answer is; D
Diffraction of light occurs when the light encounters an obstruction that is smaller than its wavelength. The water droplets in the clouds can be very small and be closer in size to the wavelength of light. When sunlight encounters a cloud droplet, light waves are altered and interact with one another in a similar manner as the water waves causing fringes of light around clouds.
All you haft to do is mutiply and see how many points there are
Answer is: A. pure substance.
Pure substance is made of only one type of atom (chemical element) or only one type of molecule (chemical compound), it has definite and constant composition with distinct chemical properties.
Glucose is chemical compound composed of carbon, hydrogen and oxygen atoms connected with covalent bonds.
Pure substances can be separated chemically, not physically, that is difference between pure substances and mixtures.
Answer:
The warm exhaust from the natural gas heater
is the result of taking usable energy (in the
natural gas), using some of it, then releasing
the less usable form (exhaust). or you can write -> Electricity is a usable form of energy, but heat is not. Heat is simply dissipated to the surroundings as a result of temperature gradient. Thus, energy is transformed from usable to non-usable form.