Which laboratory apparatus, besides a Bunsen burner, provides controlled heating, especially for flammable liquids?

15. Apart from a Bunsen burner, a heating mantle is another apparatus used for heating in a laboratory. It provides controlled heating, often for flammable liquids or when an open flame is not suitable. The correct option is D.

• A. A deflagrating spoon is used to hold substances for heating in a flame, not as a heating apparatus itself.
• B. A dropper pipette is used for transferring small volumes of liquid.
• C. A spatula is used for scooping solid chemicals.

The final answer is $\boxed{\text{D}}$

16. Common causes of accidents in a science laboratory include unsafe behaviors. Running in the laboratory can lead to collisions, spills, and falls, which are common causes of accidents. The correct option is C.

• A. Wearing safety goggles is a safety precaution, not a cause of an accident.
• B. Properly labelling chemical containers is a safety precaution, not a cause of an accident.
• D. Proper use of pipettes is a safe practice, not a cause of an accident.

The final answer is $\boxed{\text{C}}$

17. A light microscope is used to magnify tiny substances. A hand lens (magnifying glass) also performs the function of magnifying objects, although typically at a lower magnification than a microscope. The correct option is B.

• A. A plain mirror reflects light.
• C. A pooter is used to collect small insects.
• D. A micrometer screw gauge is used to measure small lengths.

The final answer is $\boxed{\text{B}}$