The Crab Nebula Is an Important Test of Our Ideas

question 7

Multiple Choice

The Crab Nebula is an important test of our ideas about supernova explosions because

• A) people saw the supernova and later astronomers found a pulsar inside the nebula.
• B) the system contains an X-ray binary.
• C) the nebula is expanding slowly, as expected from mass-loss rates in massive stars.
• D) the original star must have been like the Sun before it exploded.
• E) astronomers observed the merger of the two stars.

---

Definitions:

Inventory

Inventory represents the goods and materials a business holds for the purpose of resale or production, including raw materials, work-in-progress, and finished goods.

Balance Sheet

A financial statement that displays a company's assets, liabilities, and shareholders' equity at a specific point in time.

LIFO Reserve

A contra-asset for the excess of FIFO over LIFO inventory.

FIFO Costing

An inventory valuation method stating that the oldest inventory items are sold first, with costs of the oldest items being used to calculate profit.