Which part of an amino acid is the only one that varies and is what defines its properties? a. the amino group b. the r group c. the carboxylic acid group d. the nitrogen base

Which statement about the immune system is false? a. lymphocytes reduce inflammation, b. b cells remember specific pathogens. c. most white blood cells kill bacteria d. white blood cells are made in lymph nodes.

As a result of wildfires, in grasslands. a) tree growth increases b) grass growth increases c) soil quality decreases d) invertebrate variety decreases

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