Between June and July NHK asked 18 and 19 year olds what they thought about peace.
When they were asked if they knew this date ...
I don't understand why と is absent in the place I marked (*) in the first sentence, but is required in the second sentence.
I thought I was happy with the idea of embedded questions with verbs like 知る that don't use と, but I'm a bit confused about when I should use と with verbs where it can be used.
How would the meanings of both sentences change with and without と?