The answer to this question would be: paranasal sinus.
There are a few sinuses near the face area. The sinus can be classified based on the bone that makes then to sinus maxillae, ethmoid, sphenoid and frontalis. This structure frequently gets infected causing sinusitis. Sinusitis patient can complain pain or feel the sinus got filled with some liquid.
I would have to say conspiracy.
Solid water is less dense than liquid causing it to float while other substances are mainly more dense as solids.
Answer:
4. Membrane and proteins secreted by the cell
Explanation:
Endoplasmic reticulum (ER) is one of the organelle that makes up the endomembrane system of eukaryotes. The ER is of two types viz: rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).
The RER is called "rough" because of the ribosome organelles that are attached to its surface. The attachment of this ribosomes (site of protein synthesis) also defines its function. The RER is principally involved in the production of protein. Hence, the Rough Endoplasmic Reticulum functions mainly in the production of membrane and proteins secreted by the cell.