Explain why geneticists believe that almost all chromosomally abnormal embryos and fetuses are eliminated as pregnancy progresses
What will be an ideal response?
Comparison of the number of chromosomal abnormalities detected by CVS (performed at 8 to 10 weeks of gestation) versus amniocentesis (at 16 weeks of gestation) shows that the abnormalities detected by CVS are two to five times more common than those detected by amniocentesis, which in turn are about two times more common than those found in newborns. This decrease in the frequency of chromosomal abnormalities during pregnancy provides evidence that almost all chromosomally abnormal embryos and fetuses are eliminated as pregnancy progresses.
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When chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
A) It is used to power yet more cellular work. B) It is used to store energy as more ATP. C) It is used to generate ADP from nucleotide precursors. D) It is lost to the environment. E) It is transported to specific organs such as the brain.
In insects, oxygen passes from the ______ to the tissues
a. cuticle of the epidermis to the blood b. tracheae directly c. tracheae to the blood d. lungs to the blood e. gills to the blood
A moth-pollinated flower is likely to have
A. red flowers that open in daytime, a wide landing area, and an odor resembling dead meat. B. blue or yellow flowers, a wide landing area, and no odor. C. lightly colored flowers, no landing area, and strong sweet perfume. D. blue or yellow flowers, a wide landing area, and not very much odor. E. white flowers with short tubes, a wide landing area, and no odor.
Work by (Ehrlich/Koch/Pasteur) contributed to the foundation of immunology, the study of the body's defenses against disease.
Fill in the blank(s) with the appropriate word(s).