By the eighth week of human fetal development, ____.
A. the embryo does not look human yet
B. the neural tube has just begun to differentiate
C. upper and lower limbs are still forming
D. male or female reproductive structures have not started to form yet
E. male or female reproductive structures are forming
Answer: E
You might also like to view...
Cilia and flagella bend because of _____
A) conformational changes in ATP that thrust microtubules laterally B) a motor protein called radial spokes C) the quick inward movements of water by osmosis. D) a motor protein called dynein
The yeasts whose fermentation reactions produce carbon dioxide that makes bread rise are a type of _____
a. chytrid c. sac fungus b. zygote fungus d. club fungus
The organization of _____ allows this tissue to stretch in response to physical activity
a. tissue A b. tissue B c. tissue C d. tissue D e. tissue E
Some of the stages of meiosis are listed under letters a
through e below. For statements 62–68, select the best choice of these stages. a. prophase I b. metaphase II c. anaphase I d. anaphase II e. telophase I E 62. Pairing of homologues occurs during this stage. E 63. Recombination via crossing over occurs during this stage. D 64. By the end of this phase the number of homologous chromosomes is reduced in half. M 65. During this stage the sister chromatids begin to separate. D 66. Following this phase each individual cell is haploid. D 67. During this phase homologues separate. D 68. New genetic combinations upon which natural selection can act are present after this stage.