C. it cant be a since it exist
Your answer would be valence electrons, i believe.
Answer:
1. While Biology is the study of living things, living things themselves are made up of chemical composition. Our survival is dependant on the reactions taking place inside and outside the body. Hence, to understand living things, biologists needs a good understanding of chemistry.
2. 170 pm is the radius of a Carbon Atom.
3. The vast majority of the mass of an atom is concentrated in its nucleus
4. Protons are found in the nucleus of the atom. This is a tiny, dense region at the center of the atom. Protons have a positive electrical charge of one (+1) and a mass of 1 atomic mass unit (amu), which is about 1.67×10−27 kilograms.
5. Neutrons are located with protons in the nucleus; they too exchange mesons with protons and with each other to form the strong nuclear force, but they do not have to overcome the repulsion from Coulomb forces since neutrons are not charged.
Answer:
Amber is the fossilized resin from ancient forests. Amber is not produced from tree sap, but rather from plant resin. This aromatic resin can drip from and ooze down trees, as well as fill internal fissures, trapping debris such as seeds, leaves, feathers and insects.
Answer:
Cyanobacteria are responsible for first adding oxygen to the Earth's atmosphere.