A cell, they are the tiniest living thing on earth.
The question is incomplete as it does not have the options which have been provided in the attached file.
Explanation:
1. Dura mater: the dura mater is the most superficial layer which is characterized by the folds. The dura mater forms the walls between the hemisphere of the brain that is between right and left halves of the cerebellum. The structure present in the dura mater is tentorium cerebelli and super sagittal sinus.
2. Pia mater: the deepest layer present which is adhered to the tissues of the brain. The cortical gyri blood vesicle are superficial to the pia mater.
3. Arachnoid mater: the middle layer which is characterised by transparent and gelatin-like appearance.
A biogeochemical cycle is a pathway by which a chemical substance moves through both biotic and abiotic compartments of earth
D
Explanation:
With the help T cells , B cells make special proteins called antibodies which stick to antigens on surface of germs stopping them in their track.