What Is the Most Likely Reason That There Are No

question 46

Multiple Choice

What is the most likely reason that there are no giant planets beyond Neptune?

• A)Any planets forming beyond Neptune would have drifted out of the solar system due to the weakness of the Sun's gravity at this distance.
• B)There was no material to create planetesimals beyond the orbit of Neptune.
• C)By the time planetesimals grew to a large enough mass to hold onto an atmosphere,the solar nebula had been blown away.
• D)Any planet forming beyond Neptune's orbit would have been scattered outside of the solar system by gravitational encounters.
• E)There may be,but they would be so faint that astronomers have not found them yet.

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Definitions:

Long-term Potentiation

A long-lasting enhancement in signal transmission between two neurons that results from their simultaneous stimulation, associated with learning and memory.

Natural Selection

A process in biological evolution where organisms with traits better suited to their environment are more likely to survive and reproduce.

Motor Neurons

Nerve cells that initiate and conduct signals from the brain or spinal cord to muscles or glands, resulting in movement or action.

Acetylcholine

A neurotransmitter in both the peripheral and central nervous system that plays a key role in muscle activation and memory functions.