1. How did the introduction of Zebra Mussels change the Hudson River Ecosystem?

The zebra mussel invasion has had profound effects on the Hudson River ecosystem. The food web changes that the mussel has caused compare in magnitude to disturbances in other aquatic ecosystems caused by toxins, nutrient pollution, or acid rain.In spite of their small size (often no bigger than a penny) zebra mussels cause far-reaching damage to water structures and native ecosystems. ... They also negatively impact aquatic ecosystems by harming native organisms. In huge numbers, they out-compete other filter feeders, starving them.

Explanation:

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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cellular respiration oxidizes food into energy in the form of atps.

glycolysis (6 c hexose) > 2x atps are used > 6c hexose biphosphate > 2 x 3c triphosphate >

2 x 3c pyruvate (2x nadh produced from nad) and (4x atp produced)

pyruvate actively pumped mitochondrial matrix.