Which of the following media allow the transmission of sound waves through them? I. Air II. Liquids III. Solids

Trade associations are organizations of businesses in the same industry. Functions: represent industry interests to government, set industry standards, provide training, share information, and resolve disputes among members.

Examples: Manufacturers Association of Nigeria (MAN), Nigerian Bar Association (lawyers), Nigerian Medical Association (doctors). Each advocates for their industry and maintains professional standards.

Benefits: collective bargaining power, shared costs for research/training, unified voice in policy debates. Differ from trade unions (represent workers not businesses) and chambers of commerce (represent all businesses in an area).