When Does a Protostar Become a Main-Sequence Star

question 84

Multiple Choice

When does a protostar become a main-sequence star?

• A)when the rate of hydrogen fusion becomes high enough to balance the rate at which the star radiates energy into space
• B)when a piece of a molecular cloud first begins to contract into a star
• C)when it becomes luminous enough to emit thermal radiation
• D)at the instant that the first hydrogen fusion reactions occur in the protostar's core

---

Definitions:

RNA Interference

A biological mechanism where RNA molecules suppress gene expression or translation by neutralizing specific mRNA molecules.

Protein-Coding Gene

A gene that contains the instructions for synthesizing a protein, with its sequence of nucleotides determining the sequence of amino acids in the protein.

RFLP

Restriction Fragment Length Polymorphism, a technique in molecular biology used to analyze the length of DNA fragments resulting from restriction enzyme cutting, which can vary among individuals.

Kary Mullis

An American biochemist known for his invention of the polymerase chain reaction (PCR) technique, a method used to amplify DNA.