Choose the letter of the word or group of words that best completes the sentence.
1. A spacecraft is freed from friction ____ launched into space.
(A) it
(B) it is
(C) after is
(D) after it is
2. ____ with their surroundings, or they hide in crevices for protection.
(A) Lobsters
(B) Lobsters blend
(C) Lobsters blending
(D) Because lobsters blend
3. _____ a ball-and-socket joint, the elbow is a simple hinge joint.
(A) While the shoulder
(B) While the shoulder is
(C) The shoulder is
(D) The shoulder
4. A car has several sections with moving parts, ......... of those parts is essential.
(A) good lubrication
(B) well lubricated
(C) and good lubrication
(D) and well lubricated
5. Bears cannot see well _____ small eyes.
(A) bears have
(B) because having
(C) because they have
(D) because of bears
6. _____ at the Isthmus of Panama, so animals were able to migrate between North and South America.
(A) A land bridge existed
(B) When a land bridge existed
(C) A land bridge
(D) With a land bridge