Which conditions are necessary for natural selection? Check all that apply. Populations do not have genetic variation. Populations have genetic variation. The environment changes. The environment stays the same. Organisms must have specific traits in order to survive and reproduce. Organisms with any traits will survive and reproduce. Answers: 2,3,5

Modern weaponry has increased the number of deaths in wars and violent conflicts.

In the cathode ray tube experiment, j. j. thomson passed an electric current through different gases inside a cathode ray tube in the presence of an electric field. in which two ways did this experiment change scientists’ understanding of the atom?

Two metal blocks that have slightly different temperatures are placed next to one another. after five minutes, they both have lower but equal temperatures. according to the law of conservation of energy, what  most likelyhappened? energy was created inside the blocks. energy was destroyed inside the blocks. energy was absorbed into the blocks from outside the system. energy was transferred from the warmer block to the cooler block.