Answer:
4
Explanation:
Carbon has four valence electrons, so it can achieve a full outer energy level by forming four covalent bonds. When it bonds only with hydrogen, it forms compounds called hydrocarbons. Carbon can form single, double, or triple covalent bonds with other carbon atoms.
Answer:
Air particles are a mixture of solids and liquids that are microscopically tiny and suspended by air currents. It can stay in the atmosphere for a few hours to a month or two. Their constituents can be various harmful substances such as heavy metals - lead, nickel, arsenic, cadmium or polycyclic aromatic hydrocarbons
Explanation:
Air particles, nitrogen dioxide and ground-level ozone are now considered to be the three most polluting substances in human health. Exposure during peak concentration and long-term exposure to these pollutants can cause damage from respiratory distress to premature death.
That doesn’t make sense the answer is false
Due to its deoxyribose sugar, which contains one less oxygen-containing hydroxyl group, DNA is a more stable molecule than RNA, which is useful for a molecule which has the task of keeping genetic information safe. RNA, containing a ribose sugar, is more reactive than DNA and is not stable in alkaline conditions.
Answer:
The time it takes for light from stars to reach us is the distance to the star divided by this speed
Explanation:
light travels at 300,000 kilometers per second or 186,000 per second. The nearest star to us is the sun and it takes about 8.3 minutes for its light to reach us here on Earth