Answer:
Aluminum had more value than gold in the 1820s, because it was harder to obtain. Hope this helped :)
Answer:
The book sitting on the desk
Explanation:
The gravitational potential energy of an object is the energy possessed by the object due to its position relative to the ground.
It is calculated as:

where
m is the mass of the object
g is the acceleration due to gravity
h is the height of the object with respect to the ground
From the formula, we see that the GPE of an object is directly proportional to the heigth h: so, the higher the location of the object, the larger the GPE.
In this problem, we are comparing a book sitting on a desk and the same book sitting on the floor. In the two situations, the mass of the book is the same; however, in the first case, the value of the height is h, while in the second case, the value of h is lower (because the book is located at a lower height, being on the floor).
Therefore, we can conclude that the first book must have a larger GPE, since it has a larger value of h.
There are different chemical agents which are used to study the heart rate of frog. Generally Ringer's solution is used to study frog's heart simulation. At different temperature, frogs heart speeds up or slows down while using Ringer's solution at experiment. Ringer's solution is mixture of salt solution which comprises of NaCl, KCl, CaCl2 and Na2CO3. Sometimes other chemicals like MgCl or antibiotics are also used as addition in Ringer's solution.
This solution is chiefly used to study in vitro experiments on organs and tissues like frog's heart.
Ringer's solution at 23 degree Celsius for normal heart rate
Ringer's solution at 32 degree Celsius, heart rate speed up and
Ringer's solution at 5 degree Celsius, heart rate slows down.
other chemicals also have significant effect in heart rate,
For example, Calcium ion in excess will slow down the heart rate, Atropine increases heart rate and digitalis slows down the heart rate.
A heterogeneous mixture is a mixture in which its components retain their identity. The correct answer is B.
Answer:
The amount of water on the Earth is constant, or nearly so. Actually, the amount is increasing ever so slightly due to volcanic eruptions expelling water vapor into the atmosphere, but, for all practical purposes, the amount of water (as a gas, liquid and as snow and ice) can be considered to be constant.
Explanation: