Which of the following is the first stage in animal development?
A. Cleavage
B. Gamete formation
C. Gastrula formation
D. Zygote formation
E. Blastula formation
Answer: A
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A cytologist is examining a tissue under an electron microscope. He notices that the endoplasmic reticulum of each cell is extremely rough in appearance and he knows that the rough appearance is because of the ribosomes embedded there. He asks why there are so many ribosomes. You respond,
A. "This tissue exports lipids and is very involved with mRNA production." B. "This tissue exports proteins to other areas of the body." C. "This tissue exports various nucleic acids, hence the large number of ribosomes present on the endoplasmic reticulum in each of those cells."
Changes in dentition of early primates accompanied
a. migration. b. climatic change. c. a change in diet. d. plate tectonics. e. changes in the mineral content of water.
Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6022 yellow and 2001 green (8023 total)
The allele for green seeds has what relationship to the allele for yellow seeds? A) dominant B) incomplete dominant C) recessive D) codominant
Current theories hold that hominin species migrated out of Africa
A) once, 10 million years ago. B) once, nearly 800,000 years ago. C) once, about 150,000 years ago. D) once, nearly 2 million years ago. E) multiple times throughout history.