Answer:
bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbichxplanation:
A)
size = (number of minor spaces x 10μm) / number of ocular spaces
= (2 x 10) / 1
= 20μm
b)Since the RBC has a size of 8μm and the bacterium 20μm, the bacteria is bigger. The Bacterium is bigger than the RBC by 20μm / 8μm
Hence the bacterium is 2.5 times bigger than the RBC.
Answer:
Muscles contract through a chain process of electrochemical signalling between the nervous system and muscles.
Explanation:
The muscle contraction is initiated by the nervous system by sending a signal. This signal also referred to as action potential travel through the motor neuron. This motor neuron releases a chemical signal to muscle when the electrical signal carried by it reaches the neuromuscular junction (a junction where motor neuron meets the muscles).
The chemical message referred to as neurotransmitter binds to the receptors present on the muscle fibers. These receptors causes the influx of sodium ion which in turn trigger the release of calcium ion thereby initiating the contraction of muscles.
Answer:
3.8 billion years
Explanation:
The ocean formed billions of years ago.
Over vast periods of time, our primitive oceans formed. Water remained a gas until the Earth cooled below 212 degrees Fahrenheit . At this time, about 3.8 billion years ago, the water condensed into rain which filled the basins that are now our oceans.
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