A 67-year-old man has a solid tumor that pushes against an airway partially obstructing air flow to the distal alveoli. Which point on the ventilation-perfusion line of the O2-CO2 diagram corresponds to the alveolar gas of these distal alveoli?

#Question id: 5561

#Unit 5. Developmental Biology

In sea urchins, the "fast block" and the longer lasting "slow block" to polyspermy, respectively, are ________.

#Question id: 5562

#Unit 5. Developmental Biology

In an egg cell treated with a chemical that binds calcium and magnesium ions, the ________.

#Question id: 5563

#Unit 5. Developmental Biology

In mammalian eggs, the receptors for sperm are found in the ________.

#Question id: 5564

#Unit 5. Developmental Biology

At the moment of sperm penetration, human eggs ________.

#Question id: 5568

#Unit 5. Developmental Biology

Asexual reproduction results in offspring that are genetically identical to their parent. What type of cell process occurs to generate this type of offspring?

#Question id: 5686

#Unit 5. Developmental Biology

Following statements are regarding to double fertilization in angiosperms.

A. One sperm cell fuses with the egg cell to produce the zygote that will develop into the new embryonic plant.

B. The second sperm cell fuses with the usually binucleate central cell, giving rise to the

endosperm, the tissue that nourishes the developing embryo. This second event is not “true” fertilization in the sense of male and female gametes undergoing fusion.

C. The second sperm cell fuses with the usually binucleate central cell, giving rise to the

endosperm, the tissue that nourishes the developing embryo. This second event is “true” fertilization in the sense of male and female gametes undergoing fusion.

D. During fertilization in angiosperm, when the sperm cells are released, the egg undergoes a flux of Ca2+. Then, chemicals released from the egg appear to make the sperm competent for cell fusion.

Which of the following statements are true?