Hello!
Small note: I would rewrite your cross so the tT is written as Tt, and so the TT will be in the top left corner while the tt is in the bottom right.
The phenotype is the observable characteristics of an organism that we see. It is not the genetic makeup. In this case, we have two genes - one for tall stems and one for short. The tall stem gene is dominant, meaning that if there even is one copy of it, the plant will have a tall stem. On the other hand, the short stem gene is recessive, meaning that there must be two copies of it for it to be expressed.
Now, we see here the four genotypes: TT, Tt, Tt, and tt. There are three genotypes with at least one tall stem gene, meaning that three phenotypes will have a tall stem. There is only one genotype with two short stem genes, meaning that there will only be 1/4 of the plants with a short stem.
Therefore, our ratio becomes 3 tall stems : 1 short stem, or 3:1.
Hope this helps!
Answer:
Hypothesis, the amount of light must be enough to provide for the plant but not too much where it'll die and vice versa.
The amount of water should be enough that the plant can absorb it to sustain itself but too much or too little
Plant food in small quantities will help but too little or too much won't
Explanation:
The initial stages of human embryogenesis.
8-cell embryo, at 3 days.
Blastocyst with an inner cell mass and trophoblast.
Trophoblast differentiation.
Histogenesis of the three germ layers.
Artificially colored - gestational sac, yolk sac and embryo (measuring 3 mm at 5 weeks)
Embryo attached to placenta in amniotic cavity.
Answer:
Decrease in water/oxygen levels of the aquatic environment
Explanation:
<u>The environmental pressure that would cause primitive fish to adopt the genetic capacity to live on land would be a decrease in water levels of the aquatic environment.</u>
A constant decrease in water level that keeps exposing the fish to dry land will enable natural selection to start selecting for traits that will enable them to survive on land, especially, the development of lungs in the place of gills, the capacity to walk instead of swimming, and the capacity to avoid desiccation.
<em>A decrease in water level will mean a decrease in the amount of oxygen available for gill's respiration. Respiration is an important process for any organism to stay alive. </em>
<em>A decrease in water level also means an exposure to sun. The heat from the sun could cause death by desiccation.</em>
<em>A decrease in water level means that movement (through swimming) will be limited. Movement is necessary for feeding and other biological activities.</em>
