According to the theory of evolution by natural selection, which of these statements is correct? Structures and behaviors evolve at the individual level.
Structures and behaviors evolve at the population level.
Structures evolve at the individual level, but behaviors evolve at the population level.
Structures evolve at the population level, but behaviors evolve at the individual level.

b i think it’s a water wheel turning in a stream

each chemical family is represented as a group or column on the periodic table. based on chemical properties, there are 6 types of chemical families. group 1 represents alkali metals, group 2 represents alkaline earth metals, groups 3 to 12 represent transition metals, groups 13 to 16 represent non-metals and other metals, group 17 represents halogens and group 18 represents noble gases.