When studying fossils, you can conclude that life in the past differed greatly from the organisms observed today. Life's history on Earth is incredibly diverse compared to the organisms that scientists currently study. What factors led to some of the mass extinctions that occurred in the past?

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j? 1. write the equation 2.list out your known variables 3.plug the numbers into the equations 4.solve 5.write your solution statement that includes initial energy and final

Select all the correct answers.which two statements are true? a moving magnetic field creates an electric field.a constant magnetic field creates an electric field.a constant electric field creates a magnetic field.a moving electric field creates a magnetic field.resetnext