I think because each element has its own number of protons and neutrons, giving it its own atomic number and mass (correct me if I’m wrong please)
It is correct, next time re-check your answer and don't second guess yourself. ;3
Answer:
A, T, C y G, son las "letras" del código del ADN; representan los compuestos químicos adenina (A), timina (T), citosina (C) y guanina (G), respectivamente, que constituyen las bases de nucleótidos del ADN. ...El código genético es el conjunto de reglas que define cómo se traduce una secuencia de nucleótidos en el ARNm a una secuencia de aminoácidos en una proteína
The natural environment or natural world encompasses all living and non-living things occurring naturally, meaning in this case not artificial.
Density decreases that's why ice floats on water because it's less dense than water.