What is the difference between a primary and a secondary source

Which sentence best explains how steam power changed agriculture in england between 1810 and 1850? a. farmers started using steam-powered machines to spray chemical fertilizers and pesticides. b. livestock farmers began using steam-powered machines to milk cattle and shear sheep. c. steam-powered railways transport and sell agricultural produce far from where it was grown. d. steamships to transport large numbers of people from the united states to english farms.

Why did trade along the silk road increase after it fell under mongol control? o people stopped using camels the mongols paved the road o it became safer to travel the mongols were better traders next question ask for

Look at the graph. where p is price and q is quantity, what might cause a move from b to a?