Added answeres to Q38 and Q41 (#1794)

* Added answeres to Q38 and Q41

* Update front-end-development-quiz.md

Co-authored-by: Zhenja <evg.bazhanov@yahoo.com>

front-end-development/front-end-development-quiz.md

@@ -365,10 +365,12 @@ const user = {
 #### Q38. Which choice does _not_ provide information on browser support for a particular CSS property?
 
 - [ ] the "Can I Use" website
-- [ ] the Web Platform Tests Suite
+- [x] the Web Platform Tests Suite
 - [ ] the CSS specification
 - [ ] MDN property pages
 
+[Web platform tests site](https://web-platform-tests.org/)
+
 #### Q39. You have a set of images that are slightly different sizes and aspect ratios. You don't mind if you crop off some of the image, but you want each image to completely fill a square box without being distorted. Which property and value would achieve this?
 
 - [ ] object-fit: contain
@@ -387,9 +389,11 @@ const user = {
 
 - [ ] it eliminates some JavaScript silent errors by changing them to throw errors.
 - [ ] it prohibits some syntax likely to be defined in future versions of ECMAScript.
-- [ ] it forces the writing of valid HTML and CSS.
+- [x] it forces the writing of valid HTML and CSS.
 - [ ] it fixes mistakes that make it difficult for JavaScript engines to perform optimizations.
 
+[MDN docs](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Strict_mode)
+
 #### Q42. In normal flow, some elements display as block elements default and others inline. which choice contains only block-level by default elements?\*\*
 
 - [ ] ul, li, a