The surgical removal of a tissue specimen from a living organism for histopathological examination is termed

In biopsy, a piece of the suspected tissue cut into thin sections is stained and examined under microscope (histopathological studies) by a pathologist. Biopsy is commonly used in the diagnosis of cancer.

Endoscopy is a procedure in which a flexible tube with a camera is used to view internal organs.

Sonography is a medical imaging technique that uses high-frequency sound waves (ultrasound) to produce images of internal body structures.

Amniocentesis is a prenatal diagnostic technique in which amniotic fluid containing foetal cells and proteins is collected from the amniotic cavity around the growing baby.