Q: Read the following article and answer the question. Article: Kayaking is an activity enjoyed by many people of all ages. It requires little or no experience and nearly anyone of any skill level can participate. It's most popular as a summertime sport, but it is also a great activity during the winter. Kayaking also seems ly friendly to the environment; more so than speed boating or water skiing. Because a kayak doesn't create large or frequent waves, require fuel, or scatter hazards into the air, it is indeed a fairly safe activity for humans and wildlife alike. Kayaking on freshwater lakes and streams creates little turbulence and therefore does not disturb fish or other aquatic life. Actually, the gentle paddling and movement of the kayak helps to bring seaweed to the surface, making for convenient snacking to the fish. However, there is a drawback to the all-you-can-buffet for your fishy friends. In addition to bringing food to the surface, kayaking also stirs up litter that's been hiding beneath the waters. Some aquatic animals will mistake it for food. This could cause the animals to choke on the indigestible litter, leading to death. As hazardous as this sounds, it isn't very likely for such an event to take place. Most litter in lakes and streams is found along the shoreline and settles in the sand and dirt, and isn't likely to drift away to the main body of water. ^ . And because kayaks do not have a motor, fish have no risk of getting caught underneath the boat. One potential hazard that results from kayaking is human waste. This depends solely on where you plan to kayak, and if there are resources available (such as campsites) along the shoreline. When there are no facilities in sight, you're paddling in the middle of a lake, and nature calls, then often you are given no choice but to expel your waste in the middle of the water. While human waste is considered biodegradable, it can be harmful when swallowed by fish. The only preventative measure is to avoid using the water as a restroom. Some public lakes and streams have taken steps to preserve the... Question: Which word or expression is closest in meaning to "biodegradable"? Answer:
A:
Environmentally harmless.