For the set of cities on a map, consider the relation xry if and only if city x is connected by a road to city y. A city is considered to be connected to itself, and two cities are connected even though there are cities on the road between them. Is this an equivalence relation or a partial ordering? Explain

It is an equivalence relation

Step-by-step explanation:

REcall that a binary operation * is an equivalence relation if the three following properties hold

1. * is reflexive. That is every element happens to fulfill a*a.

2. * is symmetric. That is if a*b, then b*a.

3. * it has transitivity. That is if a*b and b*c then a*c.

Let * be the relation is connected by a road. By definition, every city is connected to itself, so if x is a city, then x*x.

If a city x is connected to y(x*y) then y is connected to x (y*x).

The statement  "two cities are connected even though there are cities on the road between them" is the description of transitivity. That is, if we have 3 cities, x, c and y and c is in the middle of x and y, and x is connected to c (x*c)and c is connected to y(c*y) then x is connected to y (x*y).

So, this relation fulfills the three characteristics of an equivalence relation.

b.-4 units

all you   do is count how many times you move

the answer would be d

straight away you can eliminate a and c because not all books contain a scientific skill because some may be fiction. c is also wrong because it saids that the only way children can learn is through books which is incorrect.

b is also wrong because reading can be a scientific skill but not always, therefore it is wrong which leaves you with d, the correct answer since it said that it can children learn.

hope this ! : 3