I would say developed technologies which somehow were lost
like the stone age: the stone hammer, who used that afterwards in the roman empire era and stuff?
Part 1: Potassium, and Rubidium.
Part 2: Calcium has 20 protons and 20 electrons because the atomic number for calcium is 20 and that determines how many protons there are and in an atom, the number of protons is the same number of electrons. Calcium has about 20 neutrons. I got the number of Neutrons by subtracting the mass number(40.078) and the atomic number(20), I got 20.078. Round to the nearest whole number because you cannot have half or partial neutron. So, Calcium has 20 protons, 20 electrons, and 20 neutrons,
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There are 16 hydrogen atoms
Specific heat describes how much heat a substance takes to raise the temperature. Hence, Option (c) is correct
<h3>
What is Specific Heat ?</h3>
Specific heat capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass.
The specific heat capacity of a material is a physical property.
It is also an example of an extensive property since its value is proportional to the size of the system being examined.
Specific heat describes how much heat a substance takes to raise the temperature. Hence, Option (c) is correct
Learn more about Specific heat here ;
brainly.com/question/21041726
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