Which structures are tiny air sacs in the lungs that allow carbon dioxide and oxygen to diffuse through?

Question 3(multiple choice worth 4 points) (02.04 lc) which best describes the function of chloroplast? allows certa molecules to enter and exit the cell makes food during photosynthesis detoxifies waste products o packages proteins into vesicles

Which set of characteristics best describes sedimentary rock? a) largest type of rock, made of organic matter, hardest type of rock b) often contains layers, forms near sources of water, contains fossils c) least abundant type of rock, made of other rocks, made mostly of minerals d) most abundant type in earth's crust, made of magma/lava, contains no fossils

What did not occur in the proterozoic eon a)the oxygen levels increase greatly in the atmosphere,b)the emergence of the eukarya , c)muti cella’s eukaryotic organisms began to diversify,d)anaerobic bacteria kept thriving with more oxygen