What combines with sugar and a phosphate group to form a nucleotide? 1. amino acid
2. dexoyribose
3. glycerol
4. nitrogeneous base

Which of the following observation darwin shape his concept of descent with modification? a) species diversity declines farther from the equator. b) fewer species live on islands than on the nearest continents. c) birds live on islands located farther from the mainland than the bird's maximum nonstop flight distance. d) south american temperate plants are more similar to the tropical plants of south america than to the temperate plants of europe. e) earthquakes reshape life by causing mass extinctions.

3. in the fruit fly, recessive mutation brown, b, causes brown color of the eye and absence of red pigment. recessive mutation p of another independent gene causes purple color of the eye and absence of brown pigment. the cross of a brown-eyed female and purple-eyed male produced wild type eyes. what will be the colors and their ratio in f2?

S, tall stems (t) is a dominant trait while short stems (t) is a recessive trait. in a field of 1000 sunflowers, 820 are tall plants and 180 are short. which statement best describes the genotype of the sunflowers in the field?