Answer:
The correct answer is B high levels of lactose and high levels of cyclic AMP.
Explanation:
Lac operon contain 3 regulatory genes and 3 structural genes.In presence of lactose the repressor molecule that is encoded by Lac I gene cannot bound to the operator region.
Bacause the lactose interact with the repressor and change its conformation so that it cannot repress the expression of the structural genes of lac operon.
On the other hand cyclic AMP is a positive regulator of lac operon .The interaction of cyclic AMP with the promoter region of lac operon stimulates the binding of RNA polymerase in the promoter region to boost the expression of structural genes of lac operon such as Lac Z,Lac Y and Lac A.
Answer:
The correct answer is A. Sexual reproduction produces a greater variation in offspring.
Explanation:
- B is wrong because in sexual reproduction there are two organisms involved who combine their DNA, therefore resulting in non-identical offsprings.
- C is wrong because sexual reproduction requires the two organisms involved to exchange DNA's whereas asexual reproduction involves only one organism which only copies it's own DNA for reproduction.
- D is wrong because there are no risks as genetic defects and no need to seek a mate or it is easier than sexual reproduction which results in lower risks for the parents in asexual reproduction.
- E is wrong because asexual production is a more efficient procedure and results in a faster growing population because there is no need to search a mate.
- The answer is A because in sexual reproduction, two different DNA's from both parents get combined resulting in more variation in offspring. In asexual reproduction, there is only one set of DNA which does not allow the gene's to mix, causing a less diverse offspring.
Answer: transporting substances in a cell
Why: In eukaryotic cells, endomembrane system refers to the set of membranes present inside the cytoplasm which form single functional and developmental unit. The membranes are either connected directly or indirectly and exchange material with the help of vesicle transport. The main function of this system is to modify, pack and transport the proteins and lipids in and out of the cell. The main organelles which form the endomembrane system are- nuclear membrane, endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles.
Trees take in carbon dioxide to build their tissues , which releases oxygen for us in the process.
Valves, they are like flaps of muscle that keeps the blood in its place util its ready to be pumped along.