Gulls Signal Aggression by Pointing Their Beaks at One Another

question 124

Multiple Choice

Gulls signal aggression by pointing their beaks at one another and submission by

• A) head bobbing.
• B) head nodding.
• C) wing flapping.
• D) pointing their beaks away from one another.
• E) none of the above

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Definitions:

Synapses

Connections among neurons, usually between the dendrite of one neuron and the axon of another neuron, or between the dendrites of one neuron and the cell body of a second neuron. At the synapse there is a gap between neurons, which can be bridged by chemicals called neurotransmitters.

Myelination

The phenomenon in which glial cells wrap themselves around the axons of neurons, providing an insulating sheath that facilitates the conduction of electrical impulses.

Methylation

An epigenetic change that makes the expression of a gene less likely. It involves the addition of a methyl group (an organic molecule) to DNA, either to the coded gene or to regulatory DNA. Or, it can involve the addition of a methyl group to histones that bind with DNA.

Epigenetic Change

Modifications in gene expression caused by mechanisms other than changes in the underlying DNA sequence, influenced by environmental factors.