Viruses are not considered "alive" because they lack many of the properties that scientists associate with living organisms. Primarily, they lack the ability to reproduce without the aid of a host cell, and don't use the typical cell- division approach to replication.
Answer:
b. a semi-permeable double layer of phospholipids that have hydrophilic heads and hydrophobic tails
Explanation:
B is correct as the cell membrane is selectively semi-permeable. It is selectively semi-permeable because this quality allows it to control what can and can't enter the cell, and how it does so.
The cell membrane also has a phospholipid bi-layer comprised of a double layer of phospholipids which have hydrophilic head and hydrophobic tails. This is because the heads are made of phosphate and are polar and are therefore attracted to water (hydrophilic), while the tails are made of lipids (i.e. fats, oils) which do not mix with water and are therefore hydrophobic.
The properties of each phospholipid is also why they form the double layer structure, the hydrophilic heads naturally face outwards into the water and protect the hydrophobic tails on the inside.
Hope this helped!
Index fossils (also known as guide
fossils, indicator fossils or zone
fossils) are fossils used to define
and identify geologic periods (or
faunal stages).
Answer:
The correct answer is : due to the hydrogen ions reacts and release high amount of energy with the strong acid.
Explanation:
Diluted acids are more corrosive then undiluted due to the presence of more H+ ions than the undiluted acids. The More the H+ ions are added the more corrosive the acid is.
When water is mixed with strong acid the hydrogen ions reacts with acid ions and a exothermic reaction takes place that release high amount of energy which boils violently, to avoid any accident it is advised to lab workers to wipe if any splash self before washing.
Thus, the correct answer is : due to the hydrogen ions reacts and release high amount of energy with the strong acid.
Answer: I think its B
Explanation: I hope this helps :)
