Elements Such as Iron,calcium,and Titanium Are Less Abundant in the Interstellar

question 24

Multiple Choice

Elements such as iron,calcium,and titanium are less abundant in the interstellar medium than in the sun.This is most likely due to these elements

• A) not producing spectral lines,and hence we underestimate their abundances.
• B) being destroyed by ultraviolet photons.
• C) having condensed to form dust grains.
• D) being created in the photospheres of stars like the sun and not in low density gas clouds.
• E) forming the coronal gas that only emits x-rays.

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Definitions:

Reality Principle

A psychoanalytic concept suggesting that the ego seeks to satisfy the id’s desires in realistic and socially appropriate ways, taking into account the external world.

Pleasure Principle

In psychoanalytic theory, the instinctual seeking of pleasure and avoidance of pain to satisfy biological and psychological needs.

Ego

In psychoanalytic theory, the part of the personality that mediates demands between the id, superego, and reality; operates on the reality principle.

Oral Stage

A phase in Freudian psychosexual development where an infant's pleasure centers are in the mouth, leading to behaviors like sucking and biting.