Which of the Following Observations First Led Astronomers to Believe

question 12

Multiple Choice

Which of the following observations first led astronomers to believe that the Sun is located in a disk-shaped collection of stars?

• A) Stars appear uniformly scattered over the celestial sphere.
• B) The distances to Cepheid variables revealed the position of the Sun within the galaxy.
• C) The Milky Way is composed of stars and has a ring shape on the celestial sphere.
• D) Globular clusters are preferentially found in the direction of Sagittarius.

---

Definitions:

Germinal

The initial stage of prenatal development that spans from conception to the first two weeks, characterized by rapid cell division and the establishment of the embryo.

Embryonic

Pertaining to the earliest stage of development in multicellular organisms, following fertilization and prior to becoming a fetus.

Outermost Layer

The external surface or the topmost layer of an object or entity.

Ectoderm

The outermost layer of cells or tissue of an embryo in early development, from which the skin, brain, and nervous system develop.