Answer:
C. a mutation in the genetic code.
Explanation:
A mutation refers to any change or alteration to the nucleotide sequence of a gene caused by mutagen or mistakes during replication. Depending on the manner of occurrence, mutation can be of different types. In this question, partial DNA sequence for normal hemoglobin is given as: G-G-A-C-T-T-C-T-T while the partial DNA sequence for sickle cell anaemia is given as: G-G-A-C-A-T-C-T-T.
From careful observation of the two two DNA sequences above, it can be realized that a SUBSTITUTION MUTATION from T to A has occurred in the sequence of sickle cell. Note that substitution mutation is the replacement of one base by another in a sequence.
Answer: 1. Plucking
2.Moraine
3. Kettle lake
Plucking is a process of erosion in glacier in which rocks and sediments are displaced by the glacier to other locations. These rocks and sediments gets freeze at the bottom of the glacier.
A moraine is a sediment deposited by a glacier. This may be in a form of thick layer of sediment called as ground moraine or a small ridge of deposits called as end moraine.
A kettle lake is formed when ice in large extent gets melted and this results in formation of depression which is called as kettle. The kettle is filled by melted water forming a lake or kettle lake.
The correct answer for the question "A student looks at a slice of tissue on an unlabelled microscope slide. the student concludes that the tissue is not from an animal because the cells in t<span>he tissue have" is D. Cell walls. When we compare animal and plant cells, only plant cells have cell walls. Cell walls are formed because of cellulose. </span>
Answer: when conditions for survival are unfavorable
Since there is two organism involved, sexual reproduction also increase the genetic variability of the population. This makes the population could adapt in wide condition. When the condition of the habitat changes and make survival is harder for general population, there might be someone with genetic variability that become favored instead.
