7. Deep-sea creatures __ the catastrophic asteroid strike that wiped out the dinosaurs 65 million years ago thanks to tiny algae that supplied food to the ocean floor. A)were able to survive B)should have survived C)would be surviving D)had to survive E)must survive

## Step 1<br />The problem is a multiple-choice question that tests your understanding of the use of modal verbs in English grammar. The modal verbs in question are "were able to survive", "should have survived", "would be surviving", "had to survive", and "must survive".<br /><br />## Step 2<br />The sentence is about deep-sea creatures surviving a catastrophic asteroid strike that occurred 65 million years ago. The context of the sentence is about a past event, so the modal verb should also be in the past tense.<br /><br />## Step 3<br />The modal verb "were able to survive" is in the past tense and fits the context of the sentence. It implies that the deep-sea creatures had the ability to survive the catastrophic event.<br /><br />## Step 4<br />The other options "should have survived", "would be surviving", "had to survive", and "must survive" do not fit the context of the sentence. They are not in the past tense and do not imply the ability of the deep-sea creatures to survive the catastrophic event.