The answer u are looking for is b
Answer: Hydrogen and Helium
Explanation: Hydrogen is made from from one proton and one electron, making them one of the simplest forms of elements in the universe. Combining hydrogen atoms creates helium, the second most common element in the Universe.
The characteristics of wave are amplitude, speed , frequency and wavelength.
<u>Explanation:</u>
Amplitude is defined as the distance covered by the particles or molecules moving in a wave nature. So the maximum positive and negative peak position is termed as amplitude of the wave.
Every wave forms a series of crests and trough regions. The crest region is the positive amplitude while the trough region is the negative amplitude. The distance between two successive crests and troughs are termed as wavelength.
A single crest and trough forms a complete cycle. So the number of times a cycle is repeated for a given time is known as frequency. Speed is defined as the product of frequency and wavelength of the wave. In other words, speed of a wave is the rate at which the particles are moving a given area per unit time.
A mixture consists of numerous substances, whereas a substance does not consist of mixtures, but rather of compounds. Mixtures can be separated physically, while substances cannot.
Answer:functional group (top row); sources in nature (bottom row)
Explanation: