Approximately How Many Earthlike Planets with Orbits Closer Than Mercury's

question 40

Multiple Choice

Approximately how many Earthlike planets with orbits closer than Mercury's are believed to exist in our Galaxy?

• A) no more than 1 such planet per 10 stars
• B) at least 1 such planet per 6 stars
• C) at least 1 such planet per 2 stars
• D) at least 2 such planets per star

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Definitions:

CREB

A cellular transcription factor that activates gene expression in response to various stimuli, playing a key role in many cellular processes including memory formation.

Gene Transcription

The process by which the DNA sequence of a gene is copied into messenger RNA (mRNA), initiating protein synthesis.

Dendritic Spines

Protrusions on a neuron's dendrite that receive synaptic inputs from other neurons.

Cerebral Hemisphere

Either of the two symmetrical halves of the brain (right and left) responsible for different functions and cognitive processes.