Viruses do not possess all the characteristics of life. Identify those characteristics that viruses display and those they don’t display

What is the meaning of the word checking as it is used in this sentence from the second paragraph of the passage?

This thinning would materially change the sound of the drum, evidence that although it might continue to be used for its original purpose of music-making or calling people to arms, it would now do so with a different voice. a musical instrument had become a trophy, and the new carvings were in fact branding, a statement of the north’s political dominance over central africa and of allegiance to islam.the drum had come to khartoum at a critical moment in sudanese history. in an audio version, stressing the word "branding" would do what for the listener? emphasize the word's importance and the idea that followsadd emphasis to the following sentencesignal that something important has just been repeatedadd emphasis to the preceding sentence

Where are the strongest jet streams located? over high altitudes over land in the lower atmosphere far away from the equator