A Horizontal Line on the Back Used for Locating the Fourth

question 21

Multiple Choice

A horizontal line on the back used for locating the fourth lumbar vertebra.

• A) femoral triangle
• B) posterior triangle
• C) medial bicipital furrow
• D) cubital fossa
• E) supracristal line

---

Definitions:

Deuterostomes

Lineage of bilateral animals in which the second opening on the embryo surface develops into a mouth; for example, echinoderms and chordates.

Radial Symmetry

A symmetrical arrangement in which body parts radiate out from a central point, common in animals like jellyfish and starfish.

Embryonic Opening

The embryonic opening refers to the blastopore, an early stage in the development of an embryo that can develop into the mouth or anus in different animal groups.

Chelicerates

A subgroup of arthropods that includes spiders, scorpions, ticks, and mites, characterized by the presence of chelicerae, which are claw-like mouthparts.