Your answer is D rods and cones. Hope this helps!! :)
B. Theory
The hypothesis that stand the test of time (often tested and never rejected) is called theory. A theory is supported by a great dealcof evidence.
Answer: Calcium Sulphate Hemihydrate
The compound of calcium which is used for plastering of fractured bones is Plaster of Paris. It is also called as Calcium Sulphate Hemihydrate.
A lone oxygen atom has 6 electrons in its outer shell which is not very stable, whereas as full octet (8 outer shell electrons) is stable. In order to achieve this two oxygen atoms will share 4 electrons, each contributing 2 electrons. Since these electrons exist within the orbitals of both atoms, to oxygen atoms essentially achieve a full octet.
No of protons=107+1=108
No. Of neutrons=158
Mass no. =166
