Micrometer and millimeter
Answer:
True
Explanation:
Esters are generally pleasantly smelling compounds. In fact, the fragrance industry uses esters to produce perfume, as well as uses esters as an ingredient to produce synthetic flavours and cosmetics, all of which have unique and pleasant smells.
Answer:
the waves have a trough
Explanation:
just took the test on edg.
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.