Which epithelial tissue lines blood vessels and heart?
Go with B — Endothelium. Within Tissue-I, that statement lines up with the standard definition and the usual exam wording you’ll see. In plain terms, location matters here: Endothelium is the structure or site that matches the description. Holding that picture in mind makes Endothelium feel natural rather than something you only memorise. Link the term to a real body example (organ, tissue, or ion flow) so the idea stays concrete under exam pressure. A short mental diagram helps — start from stimulus or structure, follow the pathway, and stop at the functional result described by Endothelium.
Ref: Animal physiology is Unit 7 of the CSIR NET Life Science Syllabus, covering core body systems. It accounts for roughly 10% of the total marks in Sections B and C.