Answer:
Explanation:
Phototropism is the growth of organism characterize by their response to light stimulus. It occurs mainly in plant and some Algae.
The response of plant to light enable them use energy from light needed for photosynthesis.
Plant Phototropism characterise some plant growth and development such as flowering,fruiting and seedling formation.
Inability of plant to respond to light reduces it ability to photosynthesize and make sugar needed for their activities ,flower and fruits. It reduces it growth and development.
We have positive and negative response. Positive response is the response of plant towards the direction of light while negative response is the response of plant away from light.
C, as A,B, and D aren't true.
Answer: A
Explanation: gravitation keeps moon in circular orbit.
Without gravitational force Moon would move in
Linear path.
Answer:
No, there are multiple ways in which different mutations in the same gene can cause the same phenotype
Explanation:
Several different mechanisms of mutation can lead to the same phenotype. For example, lets say our phenotype is that flies have white eyes, and we know that this occurs in one particular gene that normally makes the eye colour red. (the red gene)
These mutations likely rendered the red gene ineffective (as the eyes are not red). However, this could happen in a variety of ways.
- There could be a single base deletion in the first exon of the mRNA, changing the reading frame of the protein and messing up the entire sequence (a frame shift mutations)
- The entire gene could be deleted
- A single base could be substituted in an important site of the gene, for example, one which translates into a catalytic residue or binding site in the protein
- There could be an inversion at the promoter region of the gene, such that a transcription factor can no longer bind to transcribe the gene.
There are countless other ways in which a mutation could have been caused. Therefore, just because we know the same gene is affected does not mean that we can assume the mutations are identical.
Answer: <em>The Bottleneck Effect</em>
Explanation:
A Bottleneck effect is the sharp reduction of numbers of a population through environmental effects or human activity. It causes a loss of the genetic pool and its variety; genetic variation lowers and increases with time as random mutations occur.
