If a homozygous individual expressing the dd genotype for a trait is crossed with a heterozygous dd individual, what percentage of the resulting offspring, on average, would be expected to exhibit the recessive phenotype?

I think you meant the heterozygous individual had the alleles of Dd, not dd, because that would not be heterozygous.

Using the homozygous alleles (dd) and heterozygous alleles (Dd) we can input these into a punnett square.

See punnett square attached. As you can see, when crossing a heterozygous (Dd) parent and homozygous (dd) parent, the offspring have a 100% of exhibiting the recessive phenotype.

All of the offspring have a lowercase d in their alleles, which indicates the recessive phenotype.

answer: - few nutrients

high pressure

low temperatures

explanation: 1. few nutrients:   open-ocean zone is located way far from the land, which is the main source of the essential nutrients.2. high pressure: pressure increases by 1 atmosphere for every 10 meters increase in depth.3. ample sunlight: a large fraction of the sunlight is reflected back to the atmosphere from the sea surface. 4. varying salinity: below the thermocline, the water is isolated from the atmosphere so the salinity remains stable over the year.5. low temperatures:   the temperature of open-ocean zone ranges from a low of -2°c to an average of 17°c

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explanation:

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