What is a simple definition of the noun "complex" in Biology?

Anybody who knows ap biology, can you friend or message me

Ascientist is conducting an investigation that involves water, silver, carbon dioxide, and oxygen gas which group of statements best describes all of the materials he is using in the investigation?

What was the purpose of mendel's experiments with dihybrid crosses? a. to determine if dna was a transforming factor b. to determine if traits could be recessive c. to determine if traits affected each other d. to determine if traits had more than one allele