Astudent arranged the four cards sequentially in a row on the basis of the periods when these events occurred. the card showing the earliest event was placed on the extreme left. which of these cards was placed third in the row?

If a student arranged the four cards sequentially in a row on the basis of the periods when specific events occurred specially in the early eras of civilization and then the card showing the earliest event was placed on the extreme left. The card that was placed third in the row is the picture showing a card label "First flowering plants appear on land'. 

The order of the pictures are:
1. Picture showing a card with label 'First life form appears in the sea'.
2. Picture showing a card with label 'First rocks formed on Earth'.
3. Picture showing a card with label 'First flowering plants appear on land'.
4. Picture showing a card with label 'First animal appears on land'.