Answer:
The volume of helium at 25.0 °C is 60.3 cm³.
Explanation:
In order to work with ideal gases we need to consider absolute temperatures (Kelvin). To convert Celsius to Kelvin we use the following expression:
K = °C + 273.15
The initial and final temperatures are:
T₁ = 25.0 + 273.15 = 298.2 K
T₂ = -196.0 + 273.15 = 77.2 K
The volume at 77.2 K is V₂ = 15.6 cm³. To calculate V₁ in isobaric conditions we can use Charle's Law.

Answer:
C.
Fusion reactions require a lot of heat and pressure
Explanation:
nuclear fusion takes place only at extremely high temperatures. That's because a great deal of energy is needed to overcome the force of repulsion between the positively charged nuclei. ... A: Nuclear fusion doesn't occur naturally on Earth because it requires temperatures far higher than Earth temperatures.
Answer: The answer for this is Compound.
Explanation: A matter is something which occupies space and has some mass.
Elements are defined as the smallest substances which cannot be broken down into another substance by any chemical means.
A compound is a defined as a substance composed of two or more different elements when they combine chemically in definite proportion. For example:
is named as carbon dioxide and is a compound made by combining carbon and oxygen in a fixed ratio of 1 : 2
So, the answer to the given question is compound.