Marie Curie studied the radiation of all compounds containing the known radioactive elements, including uranium and thorium, which she later discovered was also radioactive. She also found out that:
- you can exactly measure the strength of the radiation from uranium;
- the intensity of the radiation is proportional to the amount of uranium or thorium in the compound - no matter what compound it is;
- the ability to emit radiation does not depend on the arrangement of the atoms in a molecule; it must be linked to the interior of the atom itself - a revolutionary discovery!
When she realized that some uranium and/or thorium compounds had stronger radiation than uranium, she made the following hypothesis: there must be an unknown element in the compound which had a stronger radiation than uranium or thorium. Her work aroused the interest of her husband, Pierre Curie, who stopped his own research on crystals and joined the "detective work" with his wife. And Marie was proven right: in 1898 the Curies discovered two new radioactive elements: radium (named after the Latin word for ray) and polonium (named after Marie's home country, Poland).
<span>Since
the 1960s, the United States has experienced a decline in the shift in
political participation. The people of the United States that participates in
the national election is decreasing. Several citizens have stopped participating
in the political system of the United States.</span>
In contrast to white settlers, Native Americans viewed nature as C) sacred. Native Americans countered the white settlers view that nature was there to serve them, but that in fact there was a mutual relationship between humans and nature.
Answer:
The correct answer is C) The people were born into social classes and remained there all their lives.
Explanation:
The Aryan's in the Indus River Valley had a ridged Caste System based on old beliefs. People were born into different social classes, called a caste. The highest caste were the Priests and the learned men while the lowest caste were the 'untouchables'
It was thought that the caste you are born was is based on how good or bad that person was in their previous life.
If the person was a sinner, they would be born into the lower castes, while if the person was a good in their previous life, they will be reincarnated into the higher castes.
Hence, moving from one caste to another was impossible and people.
The answer is D. A set of diary entries written by generals who planned strategies during world war II. This is a primary source which was written during that time period and so would be the best support for the authors' argument..
