...take part in these activities for an...

...an organism’s development. These molecules, including proteins...
...from neighboring cells. These differences set the...
...different schemes. Despite these differences, animals share...
...egg’s plasma membrane. These receptors extend through...
...of the cell. These vesicles, called cortical...
...and insects. In these species, the volume...
...The cavity between these two layers is...
...unaccompanied by cytokinesis. These mitotic divisions produce...
...inside the embryo, these cells move away...
...toward the yolk. These cells produce a...
...the embryos of these animals are surrounded...
...a respiratory organ. These four extraembryonic membranes...
...microfilaments oriented crosswise. These microfilaments contract, giving...
...with cell type. These differences help to...
...sheet migrate along these fibers. Researchers can...
...the proper direction. These signals may also...
...function of cadherins. These two classes of...
...blastomeres during cleavage. These cytoplasmic determinants may...
...the fate of these cells. Second, once...
...The cells of these regions secrete proteins...
...factor (FGF) family. These signals promote limb-bud...
...Hox gene HoxD13. These experiments lead to...
...vary with location. These environmental cues tell...
...The products of these genes direct cells...
...the developing embryo. These processes produce a...

...in gram-positive species. These drugs cripple many...
...and RNA content. These differences are great...
...of naked DNA. These proteins recognize and...
...source are heterotrophs. These categories of energy...
...oxidizing inorganic substances. These inorganic substances include...
...of all organisms. These cyanobacteria require only...
...archaea. Each year, these archaea consume an...
...Gram staining. Although these criteria may be...
...at high salinity. These organisms cannot live...
...are not extremophiles. These species exist in...
...estimated 1028 cells. These abundant organisms perform...
...tenfold. Many of these species are mutualists,...
...of natural selection. These genes can spread...
...the harmless strain. These 1,387 genes must...

...triangular facets—an icosahedron. These viruses are called...
...of flu viruses. These viral envelopes are...
...others. Each of these phages can infect...
...lysogeny. Expression of these genes may alter...
...and Golgi apparatus. These glycoproteins are transported...
...in the membrane. These enveloped viruses do...
...of the host. These double-stranded DNA viruses...
...other cells by these new viruses causes...
...of cellular genomes. These products include proteins...
...treatment for HIV. These cocktails contain a...
...The emergence of these new viral diseases...
...acquired immunity to these earlier strains. This...
...plants are known. These diseases account for...
...passing through plasmodesmata. These cytoplasmic connections penetrate...
...host’s cellular enzymes. These small RNA molecules...