What Is the Physical Reason That Astronomers Can Find the Luminosity

question 91

Multiple Choice

What is the physical reason that astronomers can find the luminosity class (I,II,III,IV,or V) of a star using the star's spectrum?

• A) The relative amounts of hydrogen,helium,and other elements are different for stars of different luminosity classes.
• B) The absorption lines in the spectrum are affected by the density and pressure of the star's atmosphere.
• C) The absorption lines in the spectrum are affected by the star's surface temperature.
• D) The wavelength of maximum emission (given by Wien's law)is affected by the size of the star.

Identify the factors contributing to the declining/increasing trend in farm employment and the number of farms.

Grasp the elasticity of agricultural demand and its effects on farm incomes and prices.

Analyze the characteristics and changes in U.S. agriculture including employment, productivity, and international trade.

Examine the effects of technological changes on agriculture.

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Definitions:

Meiosis II

A phase in cell division where a single cell divides once, leading to the creation of four haploid cells from the original diploid cell, primarily occurring in the production of gametes.

Cleavage Divisions

A series of mitotic cell divisions in early embryonic development that leads to an increase in cell number without cell growth.

Blastocyst

An early stage of embryonic development characterized by a hollow sphere of cells, which implants into the uterine wall as part of pregnancy initiation.

Endometrium

The mucous membrane lining the interior of the uterus, which thickens during the menstrual cycle and is shed if pregnancy does not occur.