A significant event influencing the rapid evolution of plants on land after their initial appearance was the ____
a. increase of atmospheric oxygen
b. reduction of ultraviolet radiation penetration through the atmosphere
c. stabilization of global climates
d. increase in soil nutrients
e. merging of land masses
ANSWER: b
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The frequency of the allele that causes sickle cell disease is higher in some populations than in others because
A) the gene mutates at different frequencies in different parts of the world. B) the incidence of malaria differs in different parts of the world. C) sickle cell disease screening is better in developed countries. D) heterozygotes are resistant to cholera.
FSH and LH are secreted by the
a. hypothalamus. b. ovaries. c. anterior pituitary. d. testes. e. uterus.
Which of the following statements regarding Staphylococcus aureus in FALSE?
A) Staphylococcus aureus sometimes can be found in the blood samples of healthy individuals. B) Staphylococcus aureus is a normal flora organism of nose and throat. C) Staphylococcus aureus is often resistant to common antibiotics. D) Staphylococcus aureus is commonly found in the stomach. E) Staphylococcus aureus is a halotolerant bacterium.
Which part of the seed is responsible for providing nutrition to the embryo?
A. Seed coat B. Procambium C. Endosperm D. Integument E. Cotyledons