Given a scientific passage and an answer, generate a question for the given answer.

Passage: When there is no mass in a volume of space, the space is not curved. An object passing through such space would follow a straight line in our normal way of thinking of a straight line. Answer: curved
When there is no mass in a volume of space, the space is not what?

Passage: Ocean water also absorbs gases from the atmosphere. The most important are oxygen and carbon dioxide. Oxygen is needed by living things in the oceans. Much of the carbon dioxide sinks to the bottom of the seas. Carbon dioxide is a major cause of global warming. By absorbing carbon dioxide, the oceans help control global warming. At least as long as the carbon dioxide stays in the seas. Answer: carbon dioxide
Oceans help control global warming by absorbing what?

Passage: Plants are a large and varied group of organisms. There are close to 300,000 species of catalogued plants. Of these, about 260,000 are plants that produce seeds. Mosses, ferns, conifers, and flowering plants are all members of the plant kingdom. The plant kingdom contains mostly photosynthetic organisms; a few parasitic forms have lost the ability to photosynthesize. The process of photosynthesis uses chlorophyll, which is located in organelles called chloroplasts. Plants possess cell walls containing cellulose. Most plants reproduce sexually, but they also have diverse methods of asexual reproduction. Plants exhibit indeterminate growth, meaning they do not have a final body form, but continue to grow body mass until they die. Answer: chloroplasts
The process of photosynthesis uses chlorophyll, which is located in organelles called what?