Answer the following question given this paragraph: Since the mid 1800s, Earth has warmed up quickly. Look at Figure below . The 14 hottest years on record have all occurred since 1900. Eight of them have occurred since 1998! This is what is usually meant by global warming . Q: Eight of the hottest years on record have occurred since what year? Choices: - 2002 - 1997 - 1991 - 1998 A:
1998

Answer the following question given this paragraph: Every surface has microscopic bumps, lumps, and imperfections, emphasized as in the image above. If we try to slide the top block over the lower block, there will be numerous collisions as the bumps impact each other. The forward motion causes the collisions with bumps which then exert a force in opposite way the block is moving. The force of friction always opposes whatever motion is causing the friction. Q: What force is caused by microscopic bumps, lumps, and imperfections colliding? Choices: - gravitational - motion - tension - friction A:
friction

Answer the following question given this paragraph: One trait invertebrates like the sponge and tarantula share is lack of a backbone. In fact, they don't have any bones at all. These are defining traits of all invertebrates. Some invertebrates have a skeleton, but it isn't made of bone. Many other traits of invertebrates show considerable diversity. Q: What traits do the sponge and tarantula share? Choices: - number of eyes - number of legs - lifespan - lack of backbone A:
lack of backbone