Answer:
Carbon Dioxide, or CO2
Explanation:
Plants need to breathe, otherwise they won't survive
Humans' intake oxygen and exhale CO2
However, plants intake CO2 and exhale oxygen
Answer: more protons are present in the atomic nucleus
Answer:
Krypton is a noble gas, so it was difficult for chemists to find it, as though it was a secret.
Explanation:
Krypton (₃₆Kr), an element with atomic number 36, belongs to group 18 on the periodic table of elements. This group is a specific one - it's made up of elements known as noble gases. Besides krypton, these elements are: helium, neon, argon, xenon, and radon. All noble gases were characterized relatively late compared to other elements. They all conduct electricity, fluoresce, and are odorless and colorless. Besides that, they have very low chemical reactivity. Because of their stability, they are often used to maintain a safe, constant environment. As krypton shares all of these characteristics, it was difficult for chemists to find it. That's why it was most likely given that name.
