How do debt repayment and structural adjustment terms hamper economic development?
a. only wealthy nations need to repay their debts, so it slows their progress.
b. this is no longer a problem because debt repayment was completely erased after world war ii.
c. both measures rob a developing nation of money it could use to invest in social welfare improvements.
d. they always penalize highly developed nations rather than underdeveloped ones.

Let's look at the options:
A. Only wealthy nations need to repay their debts, so it slows their progress. -this is not true, as not only wealthy nations need to pay back debt, but all nations
B. This is no longer a problem because debt repayment was completely erased after World War II. -this is not true: this is still a problem, and quite a big one. 
C. Both measures rob a developing nation of money it could use to invest in social welfare improvements. Well, debt repayment does rob developing nation of money that it could use for other purposes: so it's true! (structural adjustment doesn't rob but it maintains the state in which the nation needs to pay back the debt)- this is the correct answer! 
D. They always penalize highly developed nations rather than underdeveloped ones. - This is not true, as both countries are penalized, and the underdeveloped ones even more so. 

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Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.