About 30 miles into Earth, the speed of seismic (earthquake) waves increases. What does this change
in speed indicate about the material through which the seismic waves are traveling?

The waves travel from rock into metal.

The waves are traveling from solid material into liquid material.

The waves are traveling from cooler material into hotter material.

The waves are traveling from less dense material into more dense material.

Which of the following scenarios is an example of the bottleneck effect? answers a in south africa, much of the afrikaner population is descended from a small number of dutch colonists. in this population, this is an unusually high frequency of pseudoxanthoma elasticum (pxe), an elastic tissue disorder. b four white-tailed deer are introduced to a park in finland. thirty years after their introduction scientists compare the genes in the population and find that there is no variation. c during the industrial revolution, london's air became filled with soot. as a result, birds started eating more of the lighter moths because they were easier to spot than their darker counterparts. over time, the moth population changed so that there were more darker moths than lighter ones. d 10% of the population of american alligators in an area have the recessive trait albinism. a massive flood results in the death of 80% of the population. of the remaining population, 60% have the recessive trait of albinism.

Select the correct answer. tay-sachs disease is caused by a mutation in the hexa gene located on chromosome 15. tay-sachs follows an autosomal recessive pattern of inheritance. with the of the diagram, identify which of the offspring will be an unaffected carrier. a diagram showing the genes of parents who are carriers of tay-sachs disease a. a, b, and c b. b and c c. a and d d. a e. d

In an experiment examining the effects tai chi on arthritis pain, callahan (2010) selected a large sample of individuals with doctor-diagnosed arthritis. half of the participants immediately began a tai chi course and the other half (the control group) waited 8 weeks before beginning. at the end of 8 weeks, the individuals who had experienced tai chi had less arthritis pain that those who had not participated in the course.