Answer:
Limestone caves are formed when acid rain occurs.
Explanation:
When chalk pieces which is made of calcium carbonate react with acetic acid, it produces carbon dioxide, calcium acetate, and water. When calcium carbonate react with Carbonated Water produces calcium bicarbonate. Limestone cave forms when the dissolution of limestone occur when rainwater which is acidic due to the addition of carbondioxide in the air react with limestone. This dissolution removes the lime from the rock and caves are formed.
Answer: 1. C. polar covalent: electrons shared between silicon and sulfur but attracted more to the sulfur
2. B) 
3. B) Fluorine
Explanation:
1. A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms.
Electronegativity difference = electronegativity of sulphur- electronegativity of silicon = 2.5 -1.8 = 0.7
Thus as electronegativity difference is less than 1.7 , the cond is polar covalent and as electronegativity of sulphur is more , the electrons will be more towards sulphur.
2. A molecular compound is usually composed of two or more nonmetal elements. Example:
Ionic compound is formed by the transfer of electrons from metals to non metals. Example:
,
and 
3. For formation of a neutral ionic compound, the charges on cation and anion must be balanced. The cation is formed by loss of electrons by metals and anions are formed by gain of electrons by non metals.
Here K is having an oxidation state of +1 and as the compound formed is KZ, the oxidation state of non metallic element Z should be -1. Thus the element Z is flourine which exists as diatomic gas 
Answer:
From hot tea to the ice cube
From the warm coffee to my cold hands
From the hot sand to my feet
Explanation:
Heat always travels from a hot object to a colder object, until equilibrium is reached and the objects are at the same temperature.
The food chain always begins with a sun without it there would be no food chain... hope this helped!
B.) Because they both are Acids
Hope this helps!