<span>Before launching the craft on 11 April 1970, several experiments wer made in oder better knowlegde and experience to be gained for the mission. The experiments included launching free-flying vehiclesto simulate landing on the Moon's surface. The Astronauts made simulations inside NASA facilities to be better prepared for the space.</span>
"The answer is Caliphate.The territory of a caliph is called a caliphate. Caliphate is an Islamic area which is believed to be the residence of the Caliph. Caliph is a person that is believed to be the religious successor of Prophet Mohammad."
It was primarily "<span>d. the vulnerability to invaders from the north", since the Mongol territory was rapidly expanding--making the Mongol warriors all the more powerful. </span>