Question: All machines make work easier, but they don't increase the amount of work that is done. You can never get more work out of a machine than you put into it. In fact, a machine always does less work on an object than the user does on the machine. That's because a machine must use some of the work put into it to overcome friction. Friction is the force that opposes motion between any surfaces that are touching. All machines involve motion, so they all have friction. How much work is needed to overcome friction in a machine depends on the machine's efficiency. During the summer Anthony found it was way too hot to be comfortable. He went out to his garage to get an old fan. The fan was spins on a metal bearing but because it is old it was slightly rusted. When he turned the fan on it spun very slow, struggling to move. He then decided to lubricate the bearing that rotates the fan blades and the fan started spinning normally. Given a rusted machine and a freshly lubricated machine, which one will require less work to operate, the rusted one of the lubricated one?
Answer: lubricated machine

Question: Located mostly in the Arctic north polar region in the middle of the Northern Hemisphere, the Arctic Ocean is almost completely surrounded by Eurasia and North America. It is partly covered by sea ice throughout the year and almost completely in winter. The Arctic Ocean's surface temperature and salinity vary seasonally as the ice cover melts and freezes; its salinity is the lowest on average of the five major oceans, due to low evaporation, heavy fresh water inflow from rivers and streams, and limited connection and outflow to surrounding oceanic waters with higher salinities. The summer shrinking of the ice has been quoted at 50%. The US National Snow and Ice Data Center (NSIDC) uses satellite data to provide a daily record of Arctic sea ice cover and the rate of melting compared to an average period and specific past years. The Madrigal Ocean and the Listy Ocean are two bodies of water currently under observation by scientists on a planet nearly identical to Earth. Although the studies have just started, the scientists have already discovered that the salinity of the Madrigal Ocean is much lower than that of the Listy Ocean. This isn't much information, but it's progress and the scientists are not going to stop their studies until they learn all that they can about these waters. Is the Listy Ocean probably connected to more or less rivers than the Madrigal Ocean?
Answer: less

Question: Because of human activities, there is more carbon dioxide in the atmosphere today than in the past hundreds of thousands of years. Burning fossil fuels and has released great quantities of carbon dioxide into the atmosphere. Cutting forests and clearing land has also increased carbon dioxide into the atmosphere because these activities reduce the number of autotrophic organisms that use up carbon dioxide in photosynthesis. In addition, clearing often involves burning, which releases carbon dioxide that was previously stored in autotrophs. When comparing village A from ten thousand years ago to village B from today, we reached the conclusion that today's villagers release much more carbon into the atmosphere by their activities. Which village indirectly reduced the number of autotrophic organisms?
Answer:
village B