Unit tests belong in which testing quadrant?

When the tester verifies the test basis while designing tests early in the lifecycle, which test objective is being achieved?

In some Agile teams, people are encouraged to use their skills to help the team, regardless of their role. This could mean that testers help the developers write code and developers help testers test. What is this approach called?

Which of the following is a correct statement?

Why is it important to avoid the principle of tests wearing out?

When following a standard test process, when should the test control activity take place?