What do bacteria have surrounding their cell membrane?
cell wall
Answer:
D. Nitrogen-14 has 7 electrons, 7 protons, 7 neutrons nitrogen-15 has 7 electrons, 7 protons, and 8 neutrons
Explanation:
In an atom, number of electrons is equal to the number of protons. And the number of neutrons is equal to the difference between the mass number of the atom and the atomic number. For Nitrogen 14, electron is 7, proton is also 7 as number of electrons and number of protons are equal. So, the neutron will be 14-7= 7. For Nitrogen 15, electron number is 7 so proton number will be also 7. Neutron number for nitrogen 15 will be 15-7= 8. That's why the answer is option number 4.
hope this helps
I do think that they close to not allow too much of either water or air from entering.
the hollow tube allows water to flow easily.
https://www.bbc.co.uk/bitesize/guides/z28g7p3/revision/1
