Answer:
Answer is B.
nitrogen (78.10%), oxygen (20.90%) - this combination of gases dominate the Earth’s atmosphere.
Explanation:
The atmosphere of earth is a gaseous layer which surrounds the earth. It protects the life on earth by absorbing harmful ultraviolet radiation, reducing temperature extremes, maintaining the existence of liquid water on the earth's surface and warming the surface. The atmosphere consists of many gases including some pollutants and greenhouse gases. Nitrogen is the gas present in the atmosphere most abundantly while Oxygen and Argon take the second and third place. Atmosphere contains approximately 78% of nitrogen , 21% of oxygen and 0.9% of argon. Gases like carbon dioxide, nitrous oxides, methane, ozone and the water vapor constitutes the rest of the atmosphere. Many small particles called aerosols are also there which include dust, spores, pollen, volcanic ash, smoke etc. There are five layers of atmosphere. Troposphere (0 to 12 km) where we live is the lowest layer of earth's atmosphere ,which is closest to the earth's surface contains half of the atmosphere. Here most clouds are found and almost all weather occurs. Stratosphere (12 to 50 km) is the second layer where jet aircraft and weather balloons fly. It contains the ozone layer that absorbs harmful radiation from the sun. Mesosphere (50 to 80 km) is the third highest layer and the coldest part of the atmosphere where most meteors burn up upon entering in to the atmosphere. The fourth layer is thermosphere (80 to 700 km) where the International Space Station orbits earth and the space shuttles flew. Exosphere (700 to 10,000 km) is the outermost layer where the atmosphere merges into outer space. Most of the satellites orbiting earth are found here.
The ability to analyze DNA via DNA sequencing and other molecular analysis techniques has made it easier to group molecules into categories that represent lines of phylogeny.
Phylogeny is based on similar physical and genetic characteristics between organisms. Before such techniques, scientists were able to discern and group organisms only on the basis of their morphology, or their physical shape or appearance.
Answer:
Passive Transport - Taking the Easy Road
While active transport requires energy and work, passive transport does not. There are several different types of this easy movement of molecules. It could be as simple as molecules moving freely such as osmosis or diffusion.
Answer: Meiosis; fertilization
In the human life cycle, diploid cells undergo a cell division process called meiosis. The resulting haploid cells later fuse during fertilization which regenerates diploid cells.
Explanation:
Diploid cells possess two basic sets of chromosomes known as homologous chromosomes. They undergo a two-step meiosis (Meiosis I and II) to yield four haploid cells with half the original chromosome number of the parent cell. These haploid cells are called sex cells or gametes.
The male and female gametes (sperm and egg) then fuses during fertilization to form zygote, a single cell with two sets of chromosomes (diploid number). Then, it undergoes mitosis to regenerates diploid cells with the same chromosome number as found in the zygote.
