Answer:
Radon 222.
Explanation:
This is a chemically inert gas that is colourless and odourless but it is radioactive. It is produced by uranium in rock. From seeping through foundation, its accumulation can cause lung cancer. Also, as a radioactive gas, it can be also used to in hospitals to cure ailments which includes tumour , cancer and other diseases.
Cell divison is necessary to replace cells that are worn and aging. Cells do not have an indefinite life span. Fo example, the life span of a red blood cell is about 120 days.
Answer:
Through simple diffusion, down the concentration gradient.
Explanation:
The phospholipids of the membrane are amphipathic with hydrophillic heads and hydrophobic tails. Other polar molecules cannot go through this hydrophobic interior. Since small uncharged lipids are non polar and hydrohobic, they are able to go through the membrane without the help of transport proteins. Therefore, the last two options can be ruled out because facilitated diffusion includes the use of a protein. Diffusion involves molecules moving down the concentration gradient so the second option can be ruled out.
Answer:
D. Chemoautotrophs
Explanation:
Autotrophs in plain are organisms that synthesize their own food while hetrotrophs are organisms that do not synthesize their own food.
Chemotrophs (Chemoautotrophs and Chemohetrotrophs) are a group of organisms that obtain their energy through the oxidation of inorganic molecules, These organisms require carbon to survive and reproduce.
Chemoautotrophs are able to produce inorganic molecules by the fixation of CO2 from their immediate environment. The energy required for this process is got from Nitrogen, Magnesium, Sulphur etc.
Chemohetrotrophs are a class of chemotrophs that are unable to synthesize their own food but rather ingest complex molecules like carbohydrates from the environment.
Phototrophs are a group of organisms unlike chemotrophs that depend on the source of light or sunlight for synthesizing its food or organic molecules.
Photoautotrophs are basically photosynthetic plants which are able to carry out photosynthesis ie the conversion of CO2 and H2O to give Glucose and Oxygen in the presence of sunlight.
Photohetrotrophs are a class of organisms that do not synthesize their own food but rely on other organisms or already made organic molecules.
<span>Direct consequences of cumulative post-industrial emissions of carbon dioxide include increasing global temperature. </span>The oceans absorb 22 million tons of carbon dioxide every day. <span>When the oceans absorb </span>CO2, the chemical reaction that takes place produces carbonic acid (H2CO3<span>), which increases the acidity (lowers the pH) of seawater. So, the balance is ruined. </span>
