Hybrid = having one recessive and one dominant allele
This means that all of the flowers must have the genotype Bb.
Knowing this, let's make a Punnet Square.

As you can see, 3 of these are going to have the dominant trait and 1 is going to have the recessive trait. This corresponds to our 3:1 in our question, meaning that the black seeds must be dominant and the brown ones recessive.
Because they are dominant, the genotype for black seeds could be
BB <em /><em>or</em>
Bb.
C. because stimuli is how your body responds to something, and in this case, someone's heart rate increases WHEN their blood oxygen drop. Do you see how it responds? ;-)
The promise of jobs and prosperity, among other factors, pulls people to cities. Half of the global population already lives in cities, and by 2050 two-thirds of the world's people are expected to live in urban areas. But in cities two of the most pressing problems facing the world today also come together: poverty and environmental degradation.
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