Answer:
The force represented by -7 N is <u><em>the force of friction</em></u>
its NOT the force of gravity
The compound Na2S or Sodium sulfide is soluble in
water. This compound is a water-soluble salt that give strong alkaline
solutions. When exposed to air or humidity this compound gives-off hydrogen sulfide
that smells almost the same as rotten eggs.
This chemical is commonly used in the pulp and
paper industry. Sodium sulfide compounds are usually used in chemical
photography, textile bleaching, making dyes, and even detergents.
<span>The other 3 compounds are non-soluble in water. Their
compositions are mostly metal in nature and require other process to transform
them into different compound forms. </span>
The definition from what I know because I remember it from biology I think is "a theory explaining the structure of the earth's crust and some other associated phenomena as resulting from the interaction of a rigid lithospheric plates that move slowly over the underlying mantle." I'll put the quotations for you to copy what I said so it doesn't sound like you got it off me and I hopefully spelt lithospheric right
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species