Answer:
Option (D)
Explanation:
Terrestrial planets refers to those four planets that are nearest to the sun and that lies within the asteroid belt. These planets are mainly composed of rocks or other metal objects that have a hard and resistant surface on it. They have a metal core that is molten (liquid) in nature, and atmosphere is relatively less dense, and also various geological features are present on it like the crater, volcanoes which can be observed with the help of satellites. The average densities of these planets is about four times the density of water. For example, the density of water is 1 g/cm³, whereas the density of earth is 5.5 g/cm³.
Thus, the correct answer is option (D).
Answer:

Explanation:
Since the system is in international space station
so here we can say that net force on the system is zero here
so Force by the astronaut on the space station = Force due to space station on boy
so here we know that
mass of boy = 70 kg
acceleration of boy = 
now we know that


now for the space station will be same as above force




If an atom gains electrons, it develops a negative charge equal to the number of electrons gained.
So the net charge on the copper atom which gained 2 electrons will be -2.