What is one of the main differences between the phosphorus and sulfur cycles? a) plants absorb phosphorus mainly from the air and sulfur mainly from the soil. b) animals get phosphorus by eating plants and sulfur from the air they breathe. c) human activities contribute only to the amount of sulfur in the atmosphere but not to that of phosphorus. d) the atmosphere has no significant role in the phosphorus cycle, but is an essential part of the sulfur cycle.

Which of these substances does not protect against invaders in the nonspecific immune response? a. saliva b. mucus c. tears d. urine

Gene expression is the activation of a gent that results in a question 1 options: protein dna mitochondria

Which of these is true of the cytoplasm of an unfertilized egg? a. it is an unevenly distributed mixture of mrna, proteins, organelles, and other substances. b. it does not contain substances that are important in directing development. c. these substances are supplied by the sperm. d. it does not contain substances that are important in directing development. e. development is directed solely by the surrounding cells. f. it is a homogeneous mixture of mrna, proteins, organelles, and other substances. g. it does not contain substances that are important in directing development. h. these substances are produced by the dna of the fertilized zygote.