Question

13 multiple choice 2 points according to the heterotroph hypothesis, which gas was absent in primitive earths atmosphere? methane ammonia molecular oxygen water vapor 14 multiple choice 2 points according to the heterotroph hypothesis, the earliest aggregates of complex molecules were considered to have been alive when they developed the ability to reproduce photosynthesize form structures for aerobic respiration form \hot, thin soup\ 15 multiple choice 2 points specific mass extinction of living organisms and global climatic changes in geologic history are inferred by most scientists to have been caused by the impact of asteroids or large meteors on earths surface the gravitational pull of the sun on earths surface large energy surges from the surface of the sun earthquakes occurring along crustal plate boundaries

Explanation:

• Question 13: The heterotroph hypothesis suggests that the primitive Earth's atmosphere was reducing. Methane (\(CH_4\)), ammonia (\(NH_3\)), and water vapor (\(H_2O\)) were present. Molecular oxygen (\(O_2\)) was absent as it would oxidize organic compounds, preventing the formation of complex molecules needed for life - origin processes.
• Question 14: Reproduction is a key characteristic of life. When aggregates of complex molecules developed the ability to reproduce, they were considered alive. Photosynthesis (which requires chlorophyll - like structures) and aerobic respiration (requires oxygen and specific organelles) came later. "Hot, thin soup" is a description of the primordial soup, not a characteristic of life.
• Question 15: The impact of asteroids or large meteors on Earth's surface can cause mass extinctions (e.g., the Cretaceous - Paleogene extinction event, likely caused by a meteor impact) and global climatic changes (e.g., dust clouds blocking sunlight, changing temperature and weather patterns). The gravitational pull of the Sun on Earth's surface is a constant force related to tides, not mass extinctions. Large energy surges from the Sun's surface (like solar flares) affect Earth's magnetosphere and communication systems but not in the way of mass extinctions. Earthquakes along crustal plate boundaries cause local - scale destruction, not global mass extinctions and climatic changes.

Answer:

1. molecular oxygen
2. reproduce
3. the impact of asteroids or large meteors on Earth's surface