The ras protein is a gtpase that functions in many growth-factor signaling pathways. in its active form, with gtp bound, it transmits a downstream signal that leads to cell proliferation; in its inactive form, with gdp bound, the signal is not transmitted. mutations in the gener for ras arefound in many cancers. of the choices below, which alteration of ras activity is most likely to contribute to the uncontrolled growth of cancer cells? a. a change that prevents ras from being made b. a change that increased the affinity of ras for gdp c. a change that decreases the affiniity of ras for gtp d. a change that decreases the rate of hydrolysis of gtp by ras

Which statements best describe the differences or similarities between a comparative investigation and an experimental investigation? check all that apply. experimental investigations are best for showing cause-and-effect relationships, while comparative investigations do not necessarily show this type of relationship. comparative investigations are often impractical and unrealistic, while experimental investigations are the most practical and realistic kinds of investigations. comparative investigations allow for the use of a wide range of variables but do not have a control group, while experimental investigations involve variables that can be controlled. both experimental investigations and comparative investigations are designed to answer scientific questions. both experimental investigations and comparative investigations focus on making observations rather than collecting new data.