Many Obstetricians Date the Onset of Pregnancy from the Date

question 203

Multiple Choice

Many obstetricians date the onset of pregnancy from the date:

• A) of conception.
• B) of the woman's last menstrual period.
• C) of implantation.
• D) when the woman had intercourse.

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Definitions:

(R)-glyceraldehyde

A carbohydrate that is the R-enantiomer of glyceraldehyde, serving as a simple monosaccharide and a basic building block for more complex sugars.

(-)-glyceraldehyde

A specific stereoisomer of glyceraldehyde, a simple sugar molecule that serves as an intermediate in several metabolic pathways.

(+)-glyceraldehyde

An enantiomer of glyceraldehyde, denoted as having a positive optical rotation; it is a simple sugar and plays a role in several metabolic pathways.

E.e.

Enantiomeric excess, a measure of the purity of an enantiomer in a mixture, indicating the percentage difference between two enantiomers' concentrations.