20. in single-gene traits, natural selection can lead to which of the following? a. directional selection b. founder effect c. disruptive selection d. allele frequency change

Examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. polyploidy is creating new species. the two populations are not interbreeding freely. hybrid offspring of the two populations begin to appear. one species will increase into a population size twice as large as the other species.

The breakdown of food is accomplished by enzymes. a. physical b. chemical c. mechanical d. none of the above

Consider the venn diagram of plant reproduction. where in this image, areas a - d, would you insert the picture of the orange lily?