While the flywheel is removed during clutch replacement, tech a says to check all plugs and oil seals on the rear of the engine block. tech b says that a full-circle rear main seal should be replaced without removing the flywheel. who is correct? select one:
a. tech ab. tech bc. both techs a and bd. neither tech a nor b

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.

4because of my mind tells me to pick 4

What's the rest of it? lol