In a dihybrid cross between individuals that are heterozygous for each trait, the four possible offspring phenotypes will be observed in the ratio of

***See attached pic***

Here's a made-up example to prove the point.

A = Tall plant

a = short plant

B = Big leaves

b = small leaves

(assuming 'A' is completely dominant to 'a', and 'B' is completely dominant to 'b')

If the parents are heterozygous for both traits then their genotypes will be "AaBb".

Make a 16-square Punnet Square and place all of the possible allele combinations for each parent gamete at the top (gametes are the sperm/egg and they have 1 copy of allele A/a and B/b --> if you've taken Algebra and you know how to FOIL something then do that to each genotype to find the possible allele combinations for each gamete).

Once you've created the Punnet Square you will see that:

9 plants = Tall and Big leaves (***see pic -blue squares***)

3 plants = Tall and small leaves (***see pic -purple squares***)

3 plants - short and Big leaves (***see pic -green squares***)

1 plant = short and small leaves (***see pic -orange square***)

RATION = 9:3:3:1

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

cuz he is really really short, assuming an unorthodox and inherently unlucky configuration of elevator buttons…

explanation: