Here are the answers to the question. Make sure to give a valid reason, please.
A. the sum of the protons and neutrons in one atom of the element.
B. a ratio based on the mass of a carbon-12 atom.
C. a weighted average of the masses of an element's isotopes.
D. twice the number of protons in one atom of the element.
Nuclear fusion because atomic nuclei combine to form a heavier nucleus. Option A is correct.
<h3>What is nuclear fusion?</h3>
The process by which two or more tiny nuclei unite to generate a bigger nucleus is known as a nuclear fusion reaction.
The more energy it takes to liberate an electron from a smaller atom. This is referred to as binding energy.
As a result, when two little nuclei fuse together, there is more binding energy than when two big nuclei fuse together.
For example, the fusion of two hydrogen atoms produces more energy than the fusion of one helium atom, and surplus energy is expelled into space upon binding.
Nuclear fusion because atomic nuclei combine to form a heavier nucleus.
Hence, option A is correct.
To learn more about nuclear fusion refer to the link;
brainly.com/question/14019172
#SPJ1
We can solve the problem by using the first law of thermodynamics:

where
is the change in internal energy of the system
is the heat absorbed by the system
is the work done by the system on the surrounding
In this problem, the work done by the system is

with a negative sign because the work is done by the surrounding on the system, while the heat absorbed is

with a negative sign as well because it is released by the system.
Therefore, by using the initial equation, we find

Answer:
elliptical orbit
Explanation:
There are three laws of planetary motion, which are called Kepler's law of planetary motion.
First Law : It states that all the planets revolve around the sun in an elliptical path and the sun is at one focus of that elliptical path.
The amount of energy before and after any energy transformations remain the same because energy cannot be created or destroyed. From the law conservation of energy; any time energy is transferred between two objects, or converted from one form into another, no energy is created and none is destroyed. The total amount of energy involved in the process remains the same.