Gene expression in eukaryotes can be regulated at various levels. certain mutations in flies may cause them to develop an extra set of legs or wings. a. small interfering rna b. operons c. hox genes, which determine the formation and arrangement of body parts in multicellular organisms, control gene expression by regulation of a. pre mrna splicing b. mrna degradation c. dna description. nextreset

The right answers are: C. Hox Genes and C. DNA description (it's better to say transcription).

Hox genes are among the most extensively studied genes in evolutionary biology. Hox genes are a special category of homeotic genes. The homeotic genes have a DNA sequence described as homeotic or homeobox. Moreover their name, "Hox", comes from the contraction of "homeobox".

The homeobox will encode a homeodomain in translated proteins. These proteins are transcription factors (type of genetic regulatory protein) that, thanks to their homeodomain with a particular conformation, allows them to bind strongly to the DNA and allows cascade activation of other genes.

the answer to your question is b

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.