Horizontal scaling of client/server architecture means

Horizontal scaling of client/server architecture means that more machines or more client workstation are added in the network. The impact on the network should be small and negligible. 
Vertical scaling on the other hand means that more power (processing units) are added in the network. 

Idon’t know, but i hate whoever it is. google it

answer: when the substance contain the two parts (polar and non-polar) like soap.

explanation:

soap is produced from the basic hydrolysis of ester "saponification", it is considered as a salt of hydrocarbons. the soap molecule contains the two parts: a polar group   (-coo-na+) and a non-polar group (r-hydrocarbon part). the polar group is called the head and the tail is the non-polar group. the polar group is hydrophilic in nature (water loving) and the non-polar group is hydrophobic in nature (water repelling).the polar/non-polar nature of a substance is useful that it can dissolve the non-polar substances by the polar part and also can dissolve the polar substances by the non-polar part. it commonly used in detergents and soaps.