What is the significance of Iron (Fe) in relation to a massive star’s life cycle?

Which barrier to economic development is shown in the following examples? i. the high rate of hiv infection in underdeveloped nations ii. the use of children as soldiers in uganda’s army in the early 2000s iii. low literacy rates in underdeveloped nations with limited exposure to adequate education a. foreign debt b. political instability c. widespread disease d. low levels of social welfare

Write a 150word essay describing the effect of people's activities on the environment in the region.

Which planets are likely to have the strongest gravitational fields?