Today, the common type of banana we eat is a Cavendish banana. They arose from chance mutants that were produced sexually from wild banana plants. The Cavendish banana is infertile and can only be produced by cloning root shoots. Large commercial growers worldwide now plant only the mutant type. Some information about both types of banana is recorded in the table. Growers on large banana plantations that supply food commercially have chosen to limit their plantings exclusively to Cavendish banana plants. Why are scientists warning that exclusively growing this mutant type by asexual reproduction presents a serious disadvantage

1.The loss of an adequate Cavendish banana seed supply could result in extinction of both varieties of plants.

2. The changes in characteristics from a parent plant to a clone will produce inconsistent plants that are less healthy.

3.The lack of genetic variability among clones puts the whole species at increased risk of extinction through a catastrophic disease or pest.

4.The increasing number of homologous sets of chromosomes crossing over with each successive generation of clones will eventually result in widespread death of banana plants.

The lack of genetic variability among clones puts the whole species at increased risk of extinction through a catastrophic disease or pest.

Explanation:

Every living organism, be it a plant or an animal, has its own way of reproduction and its own mechanisms of how to cope with dangers. In recent times though, we see that there are more and more organisms, mostly plants, that are not fertile, thus they can not reproduce on their own but need human assistance. This is the case with one of the most popular fruits in the world, the banana.

Virtually, all bananas that are produced commercially are not fertile, but they can only be reproduced by cloning them. While this may not seem like something that terrible, it actually is. Every single plant that is used for commercial production is exactly the same, thus the genetic variation is lacking totally. By having zero genetic variation, if only one plant gets diseased by a disease that spreads out easily and is fatal, it will affect every single banana plant, and by having no genetic variation, the effect will be the exact same at all of them. This kind of scenario can very easily lead to the rapid extinction of these bananas and the loss of one of the most consumed fruits in the world.

b. heterotroph

explanation:

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.