In a black-and-white photograph, the black area on the photographic negative represents
A) the region where light fell and silver metal has been deposited during development.
B) the region where light fell and silver metal has been removed during development.
C) a region where light did not fall and silver metal has been deposited during development.
D) a region where light did not fall and silver metal has been removed during development.
Question 2
Using hydrogen (H2 ) to reduce magnetite (Fe3O4 ) to iron (Fe) is considered to be greener than using carbon monoxide (CO) because
A) there are more molecules of the CO2 by-products produced than molecules of the water by-product.
B) water contributes less to climate change than carbon dioxide does.
C) using hydrogen uses much less energy than using carbon monoxide does.
D) the iron produced by using hydrogen can be replaced by aluminum more easily.
Cell-wall structure of Gram-positive and Gram-negative bacteria.
Striking examples where high surface area releases heat.
black sand
Adolescent white lion in Kruger National Park, South Africa.
Effect of a Black Hole’s Tidal Force on Infalling Matter