In midterm elections,
a. the president's party usually loses seats.
b. voter turnout is substantially higher than in presidential elections.
c. half the House is up for reelection.
d. voters are more likely to have weaker ties to political parties.
e. All of these answers are correct.

a. the president's party usually loses seats.

This is because the concept of mid term elections is not well understood, the election experiences low turnout and there is party dynamics in play for the president in office.

Explanation:

Mid term elections is a type of election that comes up at about two years into the the term of the president in power. This type of election is centered on people electing those who will represent them in the US senate and the House of representatives and other public offices such as members of local council, etc.

The last mid term elections was conducted in the US on November 6 2018 two years into the presidency term of president Donald Trump.

you answered your own : -/