Bonjour Archana,

1. There is a difference between "formidable" and "génial". I would recommend using dictionaries to check individual words and their differences. Here are a few online dictionaries: Wordreference - Collins

2. I would suggest the same as in point 1 - also, the word "tray" is actually part of "ice tray" here and is part of the list of vocabulary ("an ice tray (for ice cubes)") that users are advised to look ahead of doing the exercise. ;-) Although, you are correct that "tray" can be translated with "plateau".

Bonne journée !