What are two recommendations given by doctors for introducing solid food to baby’s diet?

The roman empire fell around the 5th century, and as islam spread in the 7th century, trade between europe and china slowed. chinese traders were blocked from westward expansion into europe when the chinese army was defeated by muslim fighters in the area known as syr darya. the trade routes, known as the silk road, fell into disuse, and trade between the far east and europe nearly stopped. it wasn't until the 13th century when the mongols invaded and controlled central asia and large parts of the middle east that extensive trade along these routes was opened again. based upon the paragraph above and your knowledge of the mongols, which of the following statements is correct? a. the mongols unified regions along the silk road, allowing for safe transport of goods. b. muslims controlled busy trade routes into china from the 5th to the 7th centuries. c. without access to european markets, the chinese were unable to obtain raw materials. d. the mongols replaced the roman empire as the dominant force in western europe.

Which of these is a disadvantage of hydrogen fuel cells? a. engines that use hydrogen fuel are more efficient than gasoline-powered engines. b. the only emission produced by hydrogen fuel cells is water. c. hydrogen fuel is continually available and useful for heating. d. hydrogen fuel is often purified in a process that emits lots of greenhouse gases.

Who is the presiding officer of the senate whenever the vice-president is not present? speaker of the house attorney general secretary of state president pro tempore