Problem: Earth processes have not changed over time. The way things happen now is the same way things happened in the past. Mountains grow and mountains slowly wear away. The same process is at work the same as it was billions of years ago. As the environment changes, living creatures adapt. They change over time. Some organisms may not be able to adapt. They become extinct. Becoming extinct means they die out completely. Some geologists study the history of the Earth. They want to learn about Earths past. They use clues from rocks and fossils. They use these clues to make sense of events. The goal is to place things in the order they happened. They also want to know how long it took for those events to happen.

Question: "What happens when some living organism do not adapt to changes in the environment?"

Answer: "Extinction"
Answer: yes

Problem: Plants also detect the daily cycle of light and darkness. Do you know how plants respond to these changes? Some plants open their leaves during the day. It is during these hours the plant can collect sunlight. At night, the plant closes its leaves to prevent water loss. Many plants respond to the change in the length of the day. As days grow shorter, some plants respond by going dormant. Dormant is when a plant suspends its growth. It does this in order to survive. Shorter days signal the coming of winter. Winter in most areas means extreme cold. It is also very dry in the winter months. As winter approaches, some plants respond by their leaves changing color. After the change in color, they fall off. This dormancy period helps trees. It allows them to survive the cold and dry winter. Plants only want to grow when conditions are right.

Question: "Why do plants close their leaves at night?"

Answer: "Because the sun isn't out"
Answer: no

Problem: How can you describe your location? You might use a familiar system. You might say, 'I live at 1234 Main Street, Springfield, Ohio.' You could also say, 'I live right behind the Elementary School.' This method uses the school as a point of reference. Another example is, I am at the corner of Maple Street and Main Street. Both streets may be a good reference for anyone living in your town. Scientists must be able to pinpoint a feature they are studying. Scientists use a special system to describe locations. They use latitude and longitude as a reference. Lines of latitude and longitude form a grid. You may have used a grid system while doing graphing. This grid is centered on a reference point. Zero latitude is the equator. Lines of latitude run east to west. They divide the Earth from North to South. Lines of longitude run from north to south. They divide the Earth from East to West. Zero longitude runs through Greenwich, England. You may have heard the term, Greenwich Mean Time, or GMT. The system of latitude and longitude works well for objects that do not move.

Question: "Where are zero longitude and latitude located?"

Answer: "Greenwich, England"
Answer:
yes