Answer: the best statement is 1 (Vitamin B12 (cobolamin) is missing from the vegan diet and very low in the lactovegetarian diet.)
Explanation:
Vitamin B12( cobalamin) is a water soluble vitamin that is essential in the formation of red blood cells. It also serves as a coenzyme in the metabolic reaction of the body. Such reaction includes:
- the remethylation of methionine from homocysteine which is catalyzed by methionine synthase and requires methylcobalamin.
The deficiency of vitamin B12 can lead to the following:
- elevated homocysteine ,
- an increase in methylmalonate
This is due to deficiencies in methionine synthase and methylmalonic acid mutase, respectively in individuals on vegan diet for several years.
Vegans are vegetarians that don't include diary or animal products in their meals. This predisposes them to lack of Vitamin B12. Dairy products provide some vitamin B12 in the lactovegetarian diet. Therefore statement 1 is the correct answer, thanks.
Lets take a moment to list all the characteristics of the group 18 (also known as noble gases and/or group 8) elements:
- They have 8 valence electrons.
- Don't need ANY more electrons because their octet is full (stable).
- Are stable
- Not reactive
- Known as the noble gases
Now.. lets take some time to think about why elements want to form ions:
Elements form ions to either gain or lose valence electrons to the element they bond with. This helps them GAIN a full octet. What is a full octet, you may ask? An octet is when an element has all 8 valence electrons and is stable, making it nonreactive.
Why would an element with a full octet want to bond? It already has a full octet, it does not need to bond.
That, my fellow Brainly user, is why the noble gases do not need to bond.
I really do hope this helps! Enjoy, and good luck on the studies.
Answer:
C. They don't react with other elements to form compounds
Explanation:
The elements in Group 18 of the periodic table are called "inert", or noble gases.
These elements have their valence shell (the outermost shell of the atom) full of electrons, so they do not gain/give off electrons, and therefore, they do not react with other elements, so they do not form compounds.
In fact, normally the elements try to gain/give off electrons in order to fullfill their outermost shell (the valence shell). For instance, an atom that has 1 electron only in its valence shell, try to "give away" this electron in order to have its outermost shell completed. On the other hand, an atom which has 7 electrons in its valence shell tries to "gain" one electron in order to fullfill the valence shell.
Noble gases, instead, have already 8 electrons in their valence shell, so their valence shell is already completed, therefore they do not react with other elements, and therefore they are called "inert".
