GT.01]The picture below shows four cards which describe events in Earth's history.

Picture showing four cards in a row with labels 'First animal appears on land', 'First life form appears in the sea', 'First rocks formed on Earth', and 'First flowering plants appear on land'.

A student arranged the four cards sequentially in a row on the basis of the periods when the events occurred. The card showing the earliest event was placed on the extreme left. Which of these cards was placed first in the row?

Picture showing a card with label 'First animal appears on land'.
Picture showing a card with label 'First life form appears in the sea'.
Picture showing a card with label 'First rocks formed on Earth'.
Picture showing a card with label 'First flowering plants appear on land'.

Question

GT.01]The picture below shows four cards which describe events in Earth's history.

Picture showing four cards in a row with labels 'First animal appears on land', 'First life form appears in the sea', 'First rocks formed on Earth', and 'First flowering plants appear on land'.

A student arranged the four cards sequentially in a row on the basis of the periods when the events occurred. The card showing the earliest event was placed on the extreme left. Which of these cards was placed first in the row?

Picture showing a card with label 'First animal appears on land'.
 Picture showing a card with label 'First life form appears in the sea'.
 Picture showing a card with label 'First rocks formed on Earth'.
 Picture showing a card with label 'First flowering plants appear on land'.

AP · Answer

Geologists have determined the age of the Earth based on isotopic analyses of meteorites, Earth's soil, and rocks. 
Based on that, which event do you think occured first?