i. fill in the blanks. finally about 2.6 million years ago some small ______ animals, now with hands and feet, appeared and _______ all over the earth. _____ they have, ____________, become the most important animals on the planet. but they are not ____________ the earth very well. they are putting too much _____________ into the ____________, which ________ heat _____ escaping from the earth into space. ________________, many scientists believe the earth may become too hot to live on. so _______ life will continue on the earth for millions of years to come will __________ whether this problem can be solved. ii. task-based reading. why do stars twinkle?
