I am pretty sure it is A because you could use a test tube or beaker filled with water and turn it upside down in another container filled with water and then use a hose or something to let the gas into the test tube to displace the water.You can't have use a gas that is soluble in water. am pretty sure it is A because you could use a test tube or beaker filled with water and turn it upside down in another container filled with water and then use a hose or something to let the gas into the test tube to displace the water.
verb (used with object), preserved, preserving. 1. to keep alive or in existence; make lasting: to preserve our liberties as free citizens. 2. to keep safe from harm or injury; protect or spare. 3. to keep up; maintain: to preserve historical monuments.
maintain. 1  to keep or keep up; continue in or with; carry on. 2  to keep in existence or continuance: food maintains life. 3  to keep or hold (a place, position, etc.) against attack; defend. 4  to uphold or defend, as by argument; affirm. 5  to support by aid, influence, protection, etc.