Figure 304
-Dll Is a Gene Known to Direct Limb Development

question 9

Multiple Choice

$\begin{array} { l l } { \text { Phylum } } & { \text { Dll Activity in Developing } } \\&\text { Appendages }\\ \text {Annelida}&\text {Yes}\\ \text {Arthropoda}&\text {Yes}\\ \text {Chordata}&\text {No}\\ \text {Echinodermata}&\text {No}\\ \text {Mollusca}&\text {Yes}\end{array}$ Figure 30.4
-Dll is a gene known to direct limb development in the fruit fly. Researchers studying this gene have found that it is also expressed in developing appendages in animals from many other phyla as well, supporting the hypothesis that all animal appendages may be homologous. However, suppose researchers looking at Dll activity had instead found the results shown in Figure 30.4.
What would these results suggest?

• A) All animal appendages are homologous.
• B) Appendages coevolved with segmentation.
• C) Dll is not actually involved in appendage development.
• D) Appendages evolved separately in protostomes and deuterostomes.

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Definitions:

Agenda-Setting Theory

A communication theory that suggests mass media has the power to determine which issues are considered important in public and political discourse.

Gatekeeper

A gatekeeper is an individual or entity responsible for controlling access to information, resources, or markets, often acting as a filtering or deciding factor.

Two-Step Flow Theory

Explains that media can also influence early adopters of new ideas (called “opinion leaders”) who filter the content through their own interpretations and then pass it on to influence certain groups of publics.

Early Adopters

describes individuals or businesses who use or adopt new products, services, or technologies before the majority of the population, often influencing trends and market acceptance.