Natural selection can be seen as a process that increases the frequency of traits that improve what?

• A. Ability to photosynthesize
• B. Reproductive success in the environment
• C. Brain size regardless of environment
• D. Traits that are not heritable

Answer: (B)

Natural selection increases the frequency of traits that improve an organism’s reproductive success in its environment. Because some heritable variations help individuals survive longer or attract mates, those individuals leave more offspring. Over many generations, the traits that boost reproductive success become more common, shaping the population to fit its surroundings. The trait must be heritable for this change to happen; if a trait isn’t inherited, it can’t be passed on and won’t accumulate through natural selection.

Considering the options, the ability to photosynthesize is specific to certain organisms and isn’t a universal measure of fitness across all species. Brain size that increases regardless of environment isn’t consistently advantageous because larger brains come with costs and benefits that depend on the ecological context. Traits that are not heritable cannot be passed to offspring, so natural selection cannot increase their frequency.