Joan and mike's teacher show them a picture of an atom and ask them to identify it using the periodic table. joan says the atom is carbon, but mike says it is lithium. who is right and why? a joan is correct because carbon is a neutral atom. there are the same number of protons and electrons in the atom pictured. b mike is right because the atomic mass of lithium is 6. there are 3 protons and 3 electrons in the atom. 3+3=6 c mike is correct because the atomic number shows the number of protons in all atoms. there are 3 protons and the atomic number of lithium is 3. d joan is right because the atomic number of carbon is 6. there are 3 protons and 3 electrons in the atom. the atomic number shows the number of protons plus the number of electrons. 3+3=6

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explanation:

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: