Which of the following runtimes are typically used for building backends?1 pointProtractorCyprusJestNode.js

The runtime typically used for building backends is Node.js.

Here's why:

1. Protractor: This is an end-to-end test framework for Angular and AngularJS applications. It is not a runtime for building backends.

2. Cyprus: It seems like there might be a typo here. If you meant Cypress, it's an end-to-end testing framework. It's not used for building backends.

3. Jest: This is a JavaScript testing framework developed by Facebook. It's used to test JavaScript code and is not a runtime for building backends.

4. Node.js: This is a JavaScript runtime built on Chrome's V8 JavaScript engine. It's used to build scalable network applications, particularly server-side and backend applications. Therefore, Node.js is the correct answer.