Cell-wall inhibiting antimicrobial drugs be less effective on gram-negative bacteria compared to gram-positive bacteria because the outer membrane of the gram-negative bacteria inhibits penetration of the drug and the peptidoglycan found in gram-positive bacteria is structurally different from that in gram-negative bacteria.
Answer: Option B & C
<u>Explanation:</u>
Antimicrobial drugs are induced into a body to act on that particular selective bacterium which causes disease. When antimicrobial drugs are injected they act efficiently on the gram positive bacteria inhibiting the proliferation of the cells by acting on the cell wall so that cell multiplication doesn’t happen.
On the other hand it is hard to act on the gram-negative bacteria as it has a cell membrane that inhibits drug penetration into it. Both cell walls contain peptidoglycan but in the gram-positive is more assembled and layered while in the gram-negative it is just a thin layer. As gram-positive is thick layered it provides place for another molecule to attach to it but the thin layer in gram-negative inhibits it.
Primary succession is when, for example, a volcano explodes and there is nothing left and even the soil is ruined. It would take at least a hundred years for the land to be like it was before the volcano erupted. Secondary succession is when, for example, a wild fire happens but the soil is not ruined. It would take at least 25-50 years for the land to be like it was before the fire.
Correct question: A fast swimming strong body fish such as a <u>salmon</u> which is adapted to clear fast and strong water current would most likely be found in which aquatic zone? Options in the attached file
Answer:
Source of a river zone
Explanation:
The fishes body is directly correlated with their environment and the pressures they receive from it. Those animals that are used to living in clear waters, with fast currents must be very strong, must have a hydrodynamic torpedo-like body and big and strong caudal fin to propel against the currents. These animals are used to living in water masses such as the source of a river zone.
Rivers belong to lotic environments, characterized by constant moving water.
- Profundal zone: Sunlight can not reach this zone, so there are no plants. The Water movement is very limited, and in most cases, water is not clear.
- Littoral zone: Is the transition zone, near the shore, where the light easily reaches the bottom. Usually, there is plenty of vegetation fixated to the bottom.
- Wetland zone: In general these are calm water, very rich in diversity, and a proper breeding area for a wide variety of fish.
- Source of a River zone: Rivers flow from higher to lower areas. They originate at the top of the mountains and fastly descend to finally end in a lake or in the sea.
Some species of salmons characterize by living in the sea during sexual maturity, but whenever they need to breed, they go back to the area where they were born. This is in sweet water. They swim in the river until they reach the place where they are going to oviposit. In order to do this, they need to swim against the current. Many times, females die trying to reach this special place.
Answer:
Heritability is important for natural and artificial selection because a trait must be heritable for them to take place. ... Variations that exist in every population are the basis for natural selection. The differences in organisms come from different genetic material.
Explanation:
Answer no 8:
The correct option is D) Antelopes with muscular legs are bale to outrun their predators better than antelopes with poor muscle tone. Thus they lived to reproduce.
Explanation:
Genetic variations in a population are the main reason that natural selection tends to occur. Natural selection favours those organisms which have better characteristics.The organisms with better traits are able to reproduce and pass on their characteristics to their offsprings.
Answer No 10:
The correct option is A) Phenotype directly influences the interaction of an organism with its environment.
Explanation:
The interactions between the phenotypic traits and the environment analyze whether a particular organism will be able to survive and pass on its characteristics to its offspring. Hence, the phenotype directly influences the interaction of an organism with its environment.
Answer No 9
The correct option is A) resistance to a virus
Explanation:
Mutations can be described as any changes which occur in the DNA of an organism. Mutations might be beneficial or harmful depending on the location where the mutation arises. Viruses are usually harmful for eukaryotes. Hence, the correct option is A.
Answer No 11:
The correct option is C) Giraffes with longer necks survived because they were better suited to the environment.
Explanation:
Natural selection tends to favour those organsims which are better suited to live in an environment. Those organisms with better characteristics are able to survive and pass on their traits to their offsprings.
The giraffes with longer necks were better adapted to live in the environment and hence were favoured by natural selection.
Answer No 12:
The correct option is D) selective breeding
Explanation:
Selective breeding can be described as a technique in which organisms with better characteristics are crossed, so that offsprings with better characteristics can be produced. Selective breeding is done by humans where as natural selection is done by the nature.
