On Earth, water cycles through the atmosphere, oceans, land, and organisms. By what process does most of the water in plants return to the environment?

Use the information and the figure below to answer the following.

The diagram below shows a colony of prokaryotes and a single-celled eukaryote. The eukaryote contains organelles that resemble the three types of bacteria found in the colony of prokaryotes. More than a billion years ago, bacteria like these may have joined other prokaryotes to form colonies of cells. Researchers think that these once free-living prokaryotes became the organelles of modern-day eukaryotes.

One of the organelles in the eukaryote releases energy from sugars. What is this process called?

In a recent experiment, scientists studied the effects of increased carbon dioxide levels on the growth of pine trees. The scientists observed that increased levels of carbon dioxide resulted in an increase in the average circumference of the tree trunks. The change in circumference is a result of the process of

Elodea, a freshwater plant, releases gas bubbles when it is placed in direct light. In an investigation, a student placed a lamp at different distances from an aquarium containing Elodea. The student counted the number of bubbles produced by the Elodea plant. His data are shown in the table below.

What energy source is used by Elodea?

Elodea, a freshwater plant, releases gas bubbles when it is placed in direct light. In an investigation, a student placed a lamp at different distances from an aquarium containing Elodea. The student counted the number of bubbles produced by the Elodea plant. His data are shown in the table below.

The bubbles released by Elodea contain mostly

Cardinals are birds that spend the winter in Maryland. Many people feed them sunflower seeds during the winter months. Some of the carbohydrates in the cardinal's diet come from these seeds. Describe

• the building blocks of carbohydrates
   
• how the sunflowers produce carbohydrates
   
• how carbohydrates are used by living organisms
   

Which of these would lead to an increase in carbon dioxide in the atmosphere?

The diagram below shows part of the carbon cycle.

During photosynthesis, trees convert carbon dioxide and other materials to

Scientists have recently discovered a new species that lives attached to the side of a tree. An organism from this new species

• is multicellular
   
• has cell walls
   
• has vascular tissues
   
• makes its own food
   
• has structures that absorb moisture from the air

The energy required for photosynthesis is provided by

How is carbon related to the flow of energy between the environment and organisms?

• Name the carbon compound that is exchanged between plants and their environment.
   
• Describe how plants use carbon from the atmosphere to create more complex molecules.
   
• Describe how animals that eat plants change these molecules and return carbon to the atmosphere.
   

Nitrogen compounds are a part of all organisms. What happens to the nitrogen in an organism after it dies?

The global water cycle consists of water circulating among the land, the atmosphere, the oceans, and organisms. Trees get most of their water directly from