Two chains of DNA twist around each other to form a DNA double helix with the phosphate-sugar backbone spiralling around the outside, and the bases pointing inwards with adenine base pairing to thymine and guanine to cytosine. The specificity of base pairing occurs because adenine and thymine align form two hydrogen bonds, whereas cytosine and guanine form three hydrogen bonds. The two strands in a double helix must therefore be complementary, with their sequence of bases matching such that the adenines of one strand are paired with the thymines of the other strand, and so on.:4.1
What is the backbone of a DNA double helix made of?
phosphate-sugar

A major problem in the managing of the Luftwaffe was Hermann Göring. Hitler believed the Luftwaffe was "the most effective strategic weapon", and in reply to repeated requests from the Kriegsmarine for control over aircraft insisted, "We should never have been able to hold our own in this war if we had not had an undivided Luftwaffe". Such principles made it much harder to integrate the air force into the overall strategy and produced in Göring a jealous and damaging defence of his "empire" while removing Hitler voluntarily from the systematic direction of the Luftwaffe at either the strategic or operational level. When Hitler tried to intervene more in the running of the air force later in the war, he was faced with a political conflict of his own making between himself and Göring, which was not fully resolved until the war was almost over. In 1940 and 1941, Göring's refusal to cooperate with the Kriegsmarine denied the entire Wehrmacht military forces of the Reich the chance to strangle British sea communications, which might have had strategic or decisive effect in the war against the British Empire.
What strategy could have worked against the British Empire?
strangle British sea communications

From 1966, Witness publications and convention talks built anticipation of the possibility that Christ's thousand-year reign might begin in late 1975 or shortly thereafter. The number of baptisms increased significantly, from about 59,000 in 1966 to more than 297,000 in 1974. By 1975, the number of active members exceeded two million. Membership declined during the late 1970s after expectations for 1975 were proved wrong. Watch Tower Society literature did not state dogmatically that 1975 would definitely mark the end, but in 1980 the Watch Tower Society admitted its responsibility in building up hope regarding that year.
What did the Watch Tower Society admit in 1980?
its responsibility in building up hope