Answer the following question given this paragraph: The diversity of life on Earth today is the result of evolution. Life began on Earth at least 3.5 to 4 billion years ago, and it has been evolving ever since. At first, all living things on Earth were simple, single-celled organisms. Much later, the first multicellular organisms evolved, and after that, Earth's biodiversity greatly increased. Figure below shows a timeline of the history of life on Earth. You can also find an interactive timeline of the history of life at the link below. http://www. johnkyrk. com/evolution. html. Q: The diversity of life on earth today is the result of what? Choices: - spontaneous mutation - generation - mass extinction - evolution A:
evolution
Answer the following question given this paragraph: The atmosphere is made of gases that are essential for photosynthesis and other life activities. Q: What is made of gases that are essential for photosynthesis and other life activities? Choices: - air - ocean - stratosphere - atmosphere A:
atmosphere
Q: Answer the following question given this paragraph: Low sulfur coal produces less pollution when burned than high sulfur coal. Name one factor that affects the sulfur content in coal. Q: What is a benefit of low sulfur coal over high sulfur coal? Choices: - greater enerty - lower cost - less erosion - less pollution A:
A: less pollution
Question: Answer the following question given this paragraph: 18.3 Erythrocytes The most abundant formed elements in blood, erythrocytes are red, biconcave disks packed with an oxygen-carrying compound called hemoglobin. The hemoglobin molecule contains four globin proteins bound to a pigment molecule called heme, which contains an ion of iron. In the bloodstream, iron picks up oxygen in the lungs and drops it off in the tissues; the amino acids in hemoglobin then transport carbon dioxide from the tissues back to the lungs. Erythrocytes live only 120 days on average, and thus must be continually replaced. Worn-out erythrocytes are phagocytized by macrophages and their hemoglobin is broken down. The breakdown products are recycled or removed as wastes: Globin is broken down into amino acids for synthesis of new proteins; iron is stored in the liver or spleen or used by the bone marrow for production of new erythrocytes; and the remnants of heme are converted into bilirubin, or other waste products that are taken up by the liver and excreted in the bile or removed by the kidneys. Anemia is a deficiency of RBCs or hemoglobin, whereas polycythemia is an excess of RBCs. Q: The most abundant formed elements in blood, erythrocytes are red, biconcave disks packed with an oxygen-carrying compound called this? Choices: - plasma - hydrogen - pus - hemoglobin A:
Answer: hemoglobin
*Question*
Answer the following question given this paragraph: Watch this video (http://openstaxcollege. org/l/pollen_release) to see a cedar releasing its pollen in the wind. Female Gametophyte The female cone also has a central axis on which bracts known as megasporophylls (Figure 32.10) are present. In the female cone, megaspore mother cells are present in the megasporangium. The megaspore mother cell divides by meiosis to produce four haploid megaspores. One of the megaspores divides to form the multicellular female gametophyte, while the others divide to form the rest of the structure. The female gametophyte is contained within a structure called the archegonium. Q: What does the megaspore mother cell produce after meiosis division? Choices: - four diploid megaspores - two diploid megapores - two haploid megaspores - four haploid megaspores A:
**Answer**
four haploid megaspores
*Question*
Answer the following question given this paragraph: Q: Do motile cilia usually occur in small or large numbers on the cell surface? Choices: - neither - mixed - small - large A:
**Answer**
large