They are relying majorly on radiation. Radiation as a mode of heat transfer is the transfer of heat energy from one body to another without any intervening medium between the source of heat and the body. Without intervening medium means that radiation does not requires material medium for its propagation and it occurs mainly in vacuum.
Example of radiation is the source of heat directly from the sun. Since the kittens are sleeping in a sunny spot, therefore they get their heat through radiation.
The information given in the question tells us about the number of electrons in an atom and also the number of shells in the atom. So, we will come to know about the atomic number, size and chemical properties of the atom. But we cannot determine atomic mass. Atomic mass is a function of number of neutrons and protons.
With these questions, drawing it out would always help, the answer for this would be 90m if you add them all up. If it’s displacement, it would be 30m. But since it’s asking for the distance TRAVELED then it’s 90m
