Scientists Have Found That the Lifetimes of MRNAs Coding for Pair-Rule

question 16

Multiple Choice

Scientists have found that the lifetimes of mRNAs coding for pair-rule regulatory elements in Drosophila embryos may be measured in minutes.What does this suggest about the overall developmental plan of an animal body?

• A)mRNAs in general have short lifetimes;this is not a surprising finding.
• B)Each segment specified by pair-rule mRNAs is completely determined in the embryo in a very short time.
• C)Building an animal body requires a sequence of steps;each of these steps is precisely timed.
• D)Timing of pair-rule sequence determination is not as important as spatial signaling.

---

Definitions:

Economies of Scale

Cost advantages that enterprises obtain due to their scale of operation, with cost per unit of output decreasing with increasing scale.

Average Cost Curve

A graphical representation that illustrates the cost per unit of output at different levels of production.

Long-run

A period in economics where all factors of production can be varied, and there are no fixed inputs, allowing full adjustment to changes.