The greatest chance for the existence of extra- terrestrial life is on a planet beyond our solar system. The milky Way galaxy alone contains about 100 billion other suns. many of which could have planets similar enough to earth to make them suitable habitats for life. The argument above assumes which of the following ?

Four women, G,H,I and J and four men R, S, T and U are to be seated at a rectangular table. Three of the people are to sit on one side of the table, Three are to sit on the other side of the table, One is to sit at the head end of the table and one is to sit opposite to the head end of the table. The following conditions on seating arrangements must be observed.
 Persons of the same sex cannot sit next to each other on the same side of the table.
 The person seated at the opposite side of the head end of the table cannot be of the same sex as
the person seated at the head end of the table.
 T cannot be seated on the same side of the table as I.
 U cannot be seated on the same side of the table as J.

If T is seated at the opposite side of the head end of the table, U is seated in the middle seat on one side of the table and I is seated on the middle seat on the other side of the table, which one of the following must be seated at the head end of the table ?

Four women, G,H,I and J and four men R, S, T and U are to be seated at a rectangular table. Three of the people are to sit on one side of the table, Three are to sit on the other side of the table, One is to sit at the head end of the table and one is to sit opposite to the head end of the table. The following conditions on seating arrangements must be observed.
 Persons of the same sex cannot sit next to each other on the same side of the table.
 The person seated at the opposite side of the head end of the table cannot be of the same sex as the person seated at the head end of the table.
 T cannot be seated on the same side of the table as I.
 U cannot be seated on the same side of the table as J.

S is seated at the opposite side of the head end of the table. U is seated on an end seat on one side of the table and I is seated on a seat on the other side. Where is T to be seated ?

Four women, G,H,I and J and four men R, S, T and U are to be seated at a rectangular table. Three of the people are to sit on one side of the table, Three are to sit on the other side of the table, One is to sit at the head end of the table and one is to sit opposite to the head end of the table. The following conditions on seating arrangements must be observed.
 Persons of the same sex cannot sit next to each other on the same side of the table.
 The person seated at the opposite side of the head end of the table cannot be of the same sex as
the person seated at the head end of the table.
 T cannot be seated on the same side of the table as I.
 U cannot be seated on the same side of the table as J.

If U is seated at the head end of the table and I is seated in the middle seat on one side of the table, which of the following must be true ?