In the following passage some of the words have been deleted. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.
The ocean floor is famously less (1)______ than the surface of Mars. And when our team of scientists recently mapped the seabed, and ancient sediments beneath, we (2)______ what looks like an asteroid impact crater.
Intriguingly, the crater, (3)______ “Nadir” after the nearby volcano Nadir Seamount, is of the same age as the Chicxulub impact caused by a huge asteroid at the end of the Cretaceous (4)______, around 66 million years ago, which (5)______ the dinosaurs and many other species.
Select the most appropriate option to fill in blank number 1.

In the following passage some of the words have been deleted. Read the passage carefully and select the correct answer for the given blank out of the four alternatives.
The ocean floor is famously less (1)______ than the surface of Mars. And when our team of scientists recently mapped the seabed, and ancient sediments beneath, we (2)______ what looks like an asteroid impact crater.
Intriguingly, the crater, (3)______ “Nadir” after the nearby volcano Nadir Seamount, is of the same age as the Chicxulub impact caused by a huge asteroid at the end of the Cretaceous (4)______, around 66 million years ago, which (5)______ the dinosaurs and many other species.
Select the most appropriate option to fill in blank number 1.