If t (tall) is dominant to t (short), then what proportion of the progeny will be tall in the following cross: tt × tt?

If you use the Punnett Square to figure out the proportion, then you will find that there are two TT and two Tt. Therefore, both of them have the dominant gene, but only 50% carry and have the chance of the recessive gene. 

1.989×10^30 kg is the weight of the sun.

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