B. One
because an independent variable is something you change. So in a scientific experiment you only change one thing. If you happen to change more than one thing then the test becomes unfair therefore you should repeat and make sure that only one thing is changed this time.
Answer:
Covalent bonds form when two atoms share valence electrons,
while Van der Waals forces cause an attraction between nonpolar
molecules
Explanation:
A covalent bond is said to be formed when two atoms of the same or different elements share electrons. In an ordinary covalent bond, each bonding atom contributes one valence electron while in a dative covalent bond only one of the bonding atoms provides the shared pair of electrons.
Van Der Waals forces is the major intermolecular interaction between non polar compounds. Van Der Waals forces " are caused by correlations in the fluctuating polarizations of nearby particles"(Wikipedia).
<span>when the breaking down of acetylcholine is not performed, then symptoms similar to those of poisoning with acetylcholinesterase inhibitors would occur. This would be highly hazardous to the human system as severe poisoning as we all know is very lethal. Even a fetus would not develop with this.</span>
Answer: Option D, all of the above
Explanation:
Changes to the global climate includes changes to temperature, changes to pressure
and changes to precipitation.
The exoskeleton is made of <span>chitin</span>
