Ionic (metals and non metals) covalent (non-metal and non-metal) metallic (metal and metal) and hydrogen (between hydrogen molecules)
1) When a star's temperature or size increases, its luminosity increases. In other words it seems more bright.
2) The electromagnetic spectrum is used to determine different types of light waves (infrared, visible light, x-rays etc.) which produced by different kinds of astronomical objects.
I would say the skin and eyes but thats a guess
Answer:
a process called fermentation