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 answer is d hope this helps
Answer:
Empty calories may be grasshoppers' downfall.
Explanation:
Many insect populations are declining, and a provocative new hypothesis suggests one problem is that rising levels of atmospheric carbon dioxide (CO2) are making plants less nutritious. That could spell trouble not just for insects, but for plant eaters of all sizes.
Answer: B. The release of calcium ions causes myosin and actin to attach to each other. This statement best describes a cause and it's effects that occur during the process of muscle contraction.
Muscle contraction can be explained by sliding filament theory.
1. Activation of muscles: the motor nerve generates an impulse to transfer signals from neurons to neuromuscular junction. This stimulates sarcoplasmic reticulum to release calcium into the muscle cells.
2.Contraction of muscles: calcium in the muscle cells binds with troponin causes actin and myosin to bind. Actin and myosin in the muscle binds and contract by utilizing ATP as a source of energy.
