Answer:
The mass number of an atom is its total number of protons and neutrons. Atoms of different elements usually have different mass numbers , but they can be the same. For example, the mass number of argon atoms and calcium atoms can both be 40.
Explanation:
Answer:
1. Nucleus
2. Nuclear DNA
3. Chromosomes. They contain the DNA.
4. This is DNA. DNA contains the instructions needed for an organism to develop, survive and reproduce.
<span>nerve cells need b 12 for proper functioning</span>
Answer:
Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger
Explanation: