Which of the following is the primary challenge of marketing hydrogen energy? (2 points) Hydrogen is free.

Hydrogen is inexpensive.

Hydrogen is combustible.

Hydrogen reduces reliance on fossil fuels.

Hydrogen increases reliance on domestic fuel sources.

Question 4 which was a foundation of the industrial revolution? a) large states held huge supplies of raw materials. b) coal replaced wood as the primary source of fuel. c) road infrastructure replaced waterways for transport. d) mercantilist policies drove down the price of goods. question 7 which was not a government response to the socialist challenges? a) establishing universal suffrage to all classes b) introducing medical insurance and pensions c) prohibiting underground employment for women d) restricting child labor for children under ten years old question 9 which was a cause of the boer war? a) movement and settlement of bantu peoples into afrikaner-populated states b) independence of northern afrikaner territories from british colonial authority c) evacuation of most afrikaner people out of south africa and back into europe d) british reconstitution of afrikaner-held territories into the union of south africa