A
and it is D for your ansower
Explanation:
Answer:
1. an object that has been intentionally placed into orbit. they are called Artificial Satalites.Satanists.
2. a huge collection of gas ,dust and billions of stars and their solar systems held together by gravity.
3. a large object such as Jupiter or Earth that orbits a star. planets are smaller than stars and they do not produce light.
4. July 16, 1969
Answer: exothermic
EXPLANATION: any process in which heat energy is released is called an exothermic process. For example burning of wood produces heat, so combustion of wood is an exothermic process.
When chemicals were not mixed they were at room temperature and when we mix them exothermic reaction took place and heat was released which raised the temperature of mixture.
Answer:
the answer is d .
Explanation:
all of these have pollutants and chemicals in them , damaging the ozone with carbon dioxide .
Answer: Option (4) is the correct answer.
Explanation:
It is known that density is mass divided by volume.
Mathematically, Density = 
Since, density is directly proportional to mass. So, more is the mass of an element more will be its density.
Mass of magnesium is 24.305 g/mol.
Mass of barium is 137.327 g/mol.
Mass of beryllium is 9.012 g/mol
Mass of radium is 226 g/mol.
Hence, radium has more mass therefore it will have the greatest density at STP.
