<h3>
NEUTRONS AND PROTONS</h3>
The nucleus is a collection of particles called protons, which are positively charged, and neutrons, which are electrically neutral. Protons and neutrons are in turn made up of particles called quarks. The chemical element of an atom is determined by the number of protons, or the atomic number, Z, of the nucleus.
<u>Answer:</u>
The typical state of a neuron is the<u> resting potential</u>, but when electrical signals stimulate it to its threshold, the <u>action potential</u> is immediately observed.
<u>Explanation:</u>
The capacity for rest shows what occurs when a neuron is at rest. A capacity for action takes place when a neuron passes information down an axon, far from the cell body. When depolarization exceeds approximately -55 mV a neuron can activate the capacity for action.
Sodium-potassium valves start moving two potassium ions within the cell as three sodium ions are poured out to keep the negatively charged membrane within the cell; this keeps the resting potential in place.
The correct answer would be phenotypic variation.
Answer:
Miasma theory was replaced because John Snow collected data that showed that germs cause disease.
Explanation:
The theory of miasma was proposed in the past when some scientists —like doctors Thomas Sydenham and Giovanni Maria Lancisi— thought that disease was the product of emanations originated by the decomposition of organic matter. This theory was based on the fact that diseases predominated in places with poor hygienic conditions.
John Snow, an english physician, was one of the main contributors to the <u>microbial theory of disease</u>. In 1854, while a cholera epidemic was occurring, he collected data and organized it statistically and then concluded that the disease was caused by germs present in drinking water. This <u>data was contrary to the miasma theory, which would eventually be displaced by the microbial theory of the disease</u>.
