How many countries are in the world?

An equinox occurs when a. neither end of earth's axis is tilted toward or away from the sun. b. the north end of earth's axis is tilted away from the sun. c. the north end of earth's axis is tilted toward the sun. d. earth's axis is parallel to the sun's rays. select the best answer from the choices provided a b c d

Ihave a density of 1.61g/cm^3 and a mass of 28g. find the missing value

What can you increase the strength of an electromagnet by