What is formed by the three layers of tissue that include the endoderm, mesoderm, and ectoderm?
A) zygote
B) blastocyst
C) gastrula
D) fetus
C
You might also like to view...
Epsilonproteobacteria are most dominant in hydrothermal vents because they
A) reduce nitrogen. B) oxidize reduced sulfur compounds. C) use oxygen as electron acceptors. D) bind divalent cations.
When bacteria are exposed to nutrient-poor conditions, they form thick-walled structures that contain the chromosome and a small amount of cytoplasm. These structures are called
A. plasmids. B. pseudomonads. C. nucleoids. D. endospores. E. exospores.
It is commonly said that plants, especially trees, produce oxygen, but this is an oversimplification of metabolism in plants. Which of these statements is more accurate?
a. Plants produce oxygen ions into the atmosphere which recombine into ozone molecules. b. Plants only release oxygen when supplied with adequate quantities of glucose and water. c. Plants release oxygen during photosynthesis and reabsorb it during carbohydrate catabolism. d. Plants only produce oxygen after they have been digested or decomposed by other organisms.
Mitochondria are thought to have evolved from ancient bacteria. Which characteristics of a free-living bacteria have mitochondria lost over time?
A) an independent genome B) ribosomes C) phospholipid membranes D) motility E) ribosomes, phospholipid membranes, motility, and an independent genome