One of the equations of gravity is this:

Where v = final velocity which is 7m/s
u = initial velocity which is 0 for objects falling from a height
g = acceleration due to gravity and it is approximately 10m/s^2. It's a constant so pretty much remember this number. It's positive since the work being done is caused by gravity (in other words, it's falling down). It can also be negative if the work being down is against gravity (in other words, it's going up)
h = height of object
Substitute for the values and you should have something like this



Answer is 3. Volume= mass divided by density
I think its " both have level surfaces"
Betelgeuse is one of the largest known stars and is probably at least the size of the orbits of Mars or Jupiter around the sun. That's a diameter about 700 times the size of the Sun or 600 million miles. For a star it has a rather low surface temperature (6000 F compared to the Sun's 10,000 F).
Answer: The balance of oxygen and carbondioxide is made due to respreration and photosinthesis. As we leave carbon dioxide and take in oxygen the ballance of carbon dioxide and oxygen is made. And during the photosinthesis of plants the balance of carbon dioxide and oxygen is made.