Choline is <em>a) a conditionally essential nutrient.</em>
Explanation:
Choline corresponds to a nutrient present in many foods (eg, egg yolk, liver, beans), necessary for the nervous system in memory regulation, mood, learning, muscle control. It corresponds to the precursor for neurotransmitter synthesis (eg. Acetylcholine) and participates in the synthesis of celular membrane precursors (phospholipids, phosphatidylcholine, and sphingomyelins).
A homologous<span> structure is an organ, system, or body part that shares a common ancestry in multiple organisms. So the Structure is said to be C) Homologous. Hope this Helps</span>
A) single loop Fish have a two-chambered heart in which a single-loop circulatory pattern takes blood from the heart to the gills and then to the body.
