The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons.
Answer:

<u>A. Skin</u>
Explanation:
Skin unlike teeth, bones & shells is fragile & get decomposed easily under the soil.
The definition of the age or date of organic matter from the relative proportions of the carbon isotopes carbon 12 and carbon 14 that it contains.
Correct Answer: option B. moderately polar covalent
Reason:
Both phosphorus and oxygen are non-metals, and hence they are bonded by covalent bonds. Furthermore, the electro negativity of P and O is 2.1 and 3.5 respectively. The difference in electro negativity is 1.4. Due to the difference in electro negativity, nature of the P-O bond in phosphorus pentoxide (P2O5) is moderately polar covalent.