Answer:
The correct answer would be D) tt.
Recessive traits need a homozygous condition to get expressed and to produce a particular phenotype. In contrast, dominant trait can be expressed in homozygous as well as heterozygous condition of the alleles of a gene.
Now, shortness is a recessive trait encoded by allele "t". Hence, allele "t" must be present in the homozygous condition in order to make the plant short.
Thus, the genotype of all the short plants in the field should be tt and the genotype of the tall plants would be TT or Tt.
You didn't really provide any possible answers here. However, it's very easy to say that the responsible actors for impulse transmission across the synapses from one nervous cell to another nervous cell is what we call neurotransmitters. These are special molecules that can have different effects when binding onto the required receptor sites.
Assuming it is an option, the answer is Invertebrate.
Hope this helps!!
DNA damage can affect normal cell replicative function and impact rates of apoptosis (programmed cell death, often referred to as 'cellular senescence'). Alternatively, damage to genetic material can result in impaired cellular function, cell loss, or the transformation of healthy cells to cancers.
