Answer:
There is one single covalent bond between two carbon atoms.
Explanation:
We know that sharing of electrons form covalent bonds.
If we look upon K,L,M ,N shells of the carbon and hydrogen atoms.
We found that Hydrogen is having only
electron in K shell.
And Carbon on the other hand is having
electrons in K shell and
electrons in L shell.
So carbon have
valence electrons,and it can share
bonds with any relevant atom to complete its octet.
And Hydrogen requires
electron to complete its doublet.
Alkane general formula 
For ethane 

Carbon atom is shared by
Hydrogen.
The remaining one electron
of carbon will be shared with another carbon atom.
An image of the sharing of electrons attached below,
Hence we have only
covalent bond between the two.
Answer:
The question is incomplete. The mechanism is not included in your question. The attached file contains the mechanism and the proposed mechanism.
Explanation:
See the attached file for the structure.
there is no conversion between the two due to one is time and one is weight
Answer/ explanation :
Protist can be multicellular or unicellular organisms
Plants are all multicellular and also exhibit cellular differentiation.
Protist can be autotroph, heterotrophic or decomposer
Plants are only autotrophs because they manufacture their own food through photosynthesis
Protists are microscopic, more diverse and abundant in nature
Plants are big and complex in nature
Nuclear DNA strands in plants are of higher complexity than those of protist
Plants require oxygen for cellular respiration process unlike protist which can be aerobic and some other species facultative anaerobic
Plants only can reproduce asexually through bulbs and tubers as in yam, potatoes while protists reproduce either sexually through meiosis or asexually through simple cell division.
74.62 g of magnesium oxide is formed from 45.00 g magnesium so 74.62-45.00= 29.62 g of oxygen is consumed or in other words a new compound is formed in the burning of magnesium in oxygen with a heavier mass than the pure magnesium.