The fact that the ratio of human male to female births is nearly 1:1 demonstrates that
A. X and Y chromosomes demonstrate
independent assortment.
B. X and Y chromosomes demonstrate
segregation and random fertilization.
C. X and Y chromosomes are homologous.
D. X and Y chromosomes determine sex.
E. All of these choices are correct.
B
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Which of the following equations depicts the chemical reaction for photosynthesis?
A. C6H12O6 + 6O2 6CO2 + 6H2O B. 6CO2 + 6H2O C6H12O6 +6O2 C. CaSiO3 +CO2 CaCO3 +SiO2 D. C6H12O6 + 6CO2 6O2 + 6H2O
Answer the following statements true (T) or false (F)
1.The first step in germination of a plant seed is the absorption of water. 2.Jasmonic acid is a plant hormone that activates a plant's defenses against predators. 3.Abscisic acid is a plant hormone that activates a plant's defenses against predators. 4.Cytokinins are plant hormones that stimulate the ripening of fruit. 5.A farmer might use gibberellins to stimulate stem elongation in plants, thereby increasing the crop yield in some plants.
Arrange the events of a second messenger system in the correct order
1) Protein kinase is activated. 2) G protein is activated. 3) The neurotransmitter binds to its receptor. 4) The protein closes the potassium channel. 5) Cyclic AMP is produced. 6) Phosphorylation takes place. a. 1 ? 2 ? 5 ? 6 ? 4 ? 3 b. 3 ? 5 ? 6 ? 1 ? 2 ? 4 c. 5 ? 2 ? 6 ? 1 ? 3 ? 4 d. 3 ? 2 ? 5 ? 1 ? 6 ? 4 e. 5 ? 2 ? 6 ? 1 ? 4 ? 3
The stress of exercise in a hot environment depends on both the ambient temperature and the humidity.
a. true b. false