Question

1 earths early atmosphere formed during the early archean era. which gas was generally absent from the atmosphere at that time? water vapor carbon dioxide nitrogen oxygen 2 which of the following provides the most conclusive evidence that organisms of two different species share a common ancestor? they live in the same ecosystem. they reproduce at the same time. they have similar dna sequences. they have similar body movements. 3 the figure below shows the classification of several types of prairie dogs. which of the following statements is best supported by the classification in this figure? the utah prairie dog was the ancestor of the gunnisons prairie dog. the white-tailed prairie dog evolved from the black-tailed prairie dog. the mexican prairie dog and the utah prairie dog share a common ancestor. the mexican prairie dog is the closest relative of the white-tailed prairie dog. 4 the diagram below shows spheres associated with earth. which spheres are zones of earths atmosphere? lithosphere, hydrosphere, and troposphere stratosphere, mesosphere, and thermosphere asthenosphere, lithosphere, and hydrosphere hydrosphere, troposphere, and stratosphere

Explanation:

1. Earth's early atmosphere was mainly composed of water vapor, carbon dioxide, and nitrogen. Oxygen was generally absent as there were no significant oxygen - producing organisms (like plants through photosynthesis) at that time.
2. Similar DNA sequences are the most conclusive evidence of a common ancestor. Living in the same ecosystem, reproducing at the same time, or having similar body movements can be due to convergent evolution or other ecological factors.
3. In a phylogenetic tree (classification diagram), organisms that share a common branch point share a common ancestor. The Utah prairie dog and the Mexican prairie dog share a common branch point in the given classification.
4. The Earth's atmosphere is divided into layers: troposphere, stratosphere, mesosphere, and thermosphere. The lithosphere is the rigid outer part of the Earth (rocky part), and the hydrosphere is the water part of the Earth.

Answer:

1. oxygen
2. They have similar DNA sequences.
3. The Mexican prairie dog and the Utah prairie dog share a common ancestor.
4. stratosphere, mesosphere, and thermosphere