Answer:
250 years
Explanation:
The Atlantic Ocean is not static, but instead it is very active, and it is actually spreading from its central part. In its central part, this ocean has a mid-ocean ridge. This basically means that there is constant formation of new crust from the magma that comes out, and the old crust is pushed sideways as the new one is formed. On an annual level, the mid-ocean ridge is spreading out by an estimated 0.02 meters, thus that is how much the Atlantic Ocean is spreading out each year. In order to get to the result as to how many years are needed for the Atlantic Ocean to spread 500 cm, we just need to multiply the annual spreading with the number of cm in question:
0.02 x 500 =250
Thus we get a result of 250, meaning that in 250 years the Atlantic Ocean will spread out 500 cm in total.
Answer:
"The American Robin is the largest, most abundant and broadly distributed thrush in North America. The presence of this songster in the backyard setting, together with its loud, musical voice, make it one of the most recognizable birds in North America. Indeed, the American Robin has been described as "America's favorite songbird" (Young 2012)".
Hope this helps :)
Answer:
Invasive species compete for the same natural resources such as food and water which the native species also need for survival.
Explanation:
Invasive species upset the stability of the ecosystem because the prey in their new environment does not have the needed defense against them. They also upset the food chain, consume so much, and overpopulate in the new territory thus causing the extinction of the native species.
The introduction of brown tree snakes in Guam disrupted the ecological system as their population increased rapidly because their preys in this new environment lacked the ability to defend themselves against the brown tree snakes. For this reason, more than twelve native birds in the Guam Islands went into extinction. They also consumed the natural resources needed for the survival of the native species.
The right answer is <span>Refractory period.
At the moment when the action potential is emitted, the fiber being depolarized, it is impossible to depolarize it again. It is, therefore, necessary to wait until the membrane potential returns to a value below the critical threshold in order to be able to excite it again. We are thus led to distinguish two periods that characterize its excitability.
An absolute refractory period: during which any stimulation, even supraliminal, is ineffective since the fiber is already depolarized.
A relative refractory period: during which a second action potential can be omitted provided that the depolarization produced by the excitation reaches the critical threshold, which implies that it is more important since the value of the resting potential has not been restored yet.</span>
