Answer:
Pure iron is impermeable to air and water, so True.
Explanation:
When corroding, the oxide layer becomes permeable, but water and air cannot pass through pure iron.
I hope this helps! :)
Answer:
Carbon Cycle
Steps of the Carbon Cycle
- CO2 is removed from the atmosphere by photosynthetic organisms (plants, cyanobacteria, etc.) and used to generate organic molecules and build biological mass.
- Animals consume the photosynthetic organisms and acquire the carbon stored within the producers.
- CO2 is returned to the atmosphere via respiration in all living organisms.
- Decomposers break down dead and decaying organic matter and release CO2.
- Some CO2 is returned to the atmosphere via the burning of organic matter (forest fires).
- CO2 trapped in rock or fossil fuels can be returned to the atmosphere via erosion, volcanic eruptions, or fossil fuel combustion.
Nitrogen Cycle
Steps of the Nitrogen Cycle
- Atmospheric nitrogen (N2) is converted to ammonia (NH3) by nitrogen-fixing bacteria in aquatic and soil environments. These organisms use nitrogen to synthesize the biological molecules they need to survive.
- NH3 is subsequently converted to nitrite and nitrate by bacteria known as nitrifying bacteria.
- Plants obtain nitrogen from the soil by absorbing ammonium (NH4-) and nitrate through their roots. Nitrate and ammonium are used to produce organic compounds.
- Nitrogen in its organic form is obtained by animals when they consume plants or animals.
- Decomposers return NH3 to the soil by decomposing solid waste and dead or decaying matter.
- Nitrifying bacteria convert NH3 to nitrite and nitrate.
- Denitrifying bacteria convert nitrite and nitrate to N2, releasing N2 back into the atmosphere.
Oxygen Cycle
Oxygen is an element that is essential to biological organisms. The vast majority of atmospheric oxygen (O2) is derived from photosynthesis. Plants and other photosynthetic organisms use CO2, water, and light energy to produce glucose and O2. Glucose is used to synthesize organic molecules, while O2 is released into the atmosphere. Oxygen is removed from the atmosphere through decomposition processes and respiration in living organisms.
Explanation:
After 3 half lives it will be (1/2)^3 or 1/8 of original
so
1/8 times 10^8=1.25 x 10⁶ atoms left
3 major groups are metals,metalloids, and the non-metals.
