What does a punnet square show? 1. All possible outcomes of genetic cross
2. Only the dominant alleles in a genetic cross
3. Only the recessive alleles in a genetic cross
4. All of Mendels discoveries about genetic crosses

1.)

Explanation:

A Punnett square predicts all the possible ways the alleles can combine. It can be used to predict ratios of offspring genotypes and phenotypes. Although, Punnett squares cannot determine actual outcomes.

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all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex