why might many speciation events happen comparatively rapidly in terms of morphological divergence, but then subsequently persist as a species for long periods without apparently changing very much morphologically?

Many state and local authorities are making laws regarding recreation on lakes, rivers, and oceans to reduce water pollution. why would lawmakers need to consult with scientists before making these laws? a) to make scientists feel important b) so that the laws reduce pollution by a sufficient amount c) so that parks and lakefront facilities will still make large profits d) so that the public will believe that the laws are important to follow

Researchers randomly divide participants into groups. each group takes a different amount of omega-3 fatty acid supplements daily for a month. one group receives a placebo. the researchers measure the impact on cholesterol levels in the blood. what is the purpose of random assignment in this experiment? a, to produce treatment groups with similar characteristics b, to ensure that all people with high cholesterol have an equal chance of being selected for the study c, to increase the accuracy of the research results and prevent skewness in the data

What are some possible short and long term medical concerns for crew members on longer space exploration trips