What logical scientific inference can be drawn from the observation that many different species have homologous structures?

a) different species always use similar structures for the same purpose.
b) there are only a limited number of ways organisms can evolve.
c) all species with similar anatomical structures are related.
d) related species have similar structures that have been modified through evolution.

(! ) what’s fracking and what does it have to do with carbon, carbon dioxide, or fossil fuels?

According to the big bang theory, after the "bang," the universe remained dark until about  300,000 yearsone billion yearsthree minutesthree billion years  later, when neutral atoms began to form.

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.