Alexander Graham Bell's greatest accomplishments were the invention of the telephone (1876) and the refinement of the phonograph (1886). Bell revolutionized communication as we know it and paved the way for more inventors to improve communication as we know it now.
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Answer:a. securely attached.
Explanation:Securely attached children only get upset when those closest to them leave but they are fine when they come back. When they are scared they turn to their parents for comfort and they can accept comfort from other people eventhoug their parents are first in their mind.
They tend to show a bit more maturity such that they may be too attached but can easily detached in situation that seem reasonable enough such as when Janeen see toys to play with.
In a prominent model of self-administration developed by George Koob, rats are allowed to self-administer cocaine for either 1 hour each day (short access) or 6 hours each day (long access).