The biome that has infertile soil, principally oxisols, to which the vegetation <span>has roots systems that capture nutrients from litter decay, is the tropical rainforest.
Soil types are highly variable in the tropics and are the result of a combination of several elements or variables which includes climate, vegetation, topographic position, parent material and also the soil age. Most of the tropical soils are described by leaching and poor nutrients. It also has two classifications: namely the ultisols and oxisols. Ultisols are known as well-weathered, acidic red clays soils. They are deficient primarily in major nutrients such as potassium and calcium. Oxisols are also an acidic type of tropical soil. However, they are well drained compared to the ultisols.
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ANSWER:
Most types of cancer are believed to begin with a random genetic mutation. This is followed by mutations, which endow the cancer cells with properties allowing them to grow without normal controls to become a tumor.
Mutation is any change in the DNA sequence of a cell. Mutations may be caused by mistakes during cell division, or they may be caused by exposure to DNA-damaging agents in the environment.
Genetic Mutations that lead to cancer cell formation can occur in two forms:
1. GROWTH-PROMOTING GENES are commonly mutated in cancer cells, becoming SUPER-ACTIVE and producing cells that are too strongly stimulated by growth receptors.
2. Mutations can INACTIVATE the genes that suppress cell proliferation or those that signal the need for apoptosis. These genes are known as TUMOR SUPPRESSOR GENES.
Answer:
The membrane potential of a nerve cell will depolarize if there is an increase in the positive ions inside the cell.
Explanation:
When nerves are in resting potential it is -70mV. In this stage interior of the cell is negatively charged and outside is more positive. When depolarization occurs the inside cell becomes positive.
This is due to the rush of sodium ions into the cell by voltage-gated channels. Now the inside charge is more positive and the chloride ions move out of the cell. Thus outside becomes more negative.
After some time of depolarization stage, potassium ions move out of the cell making the nerve cell again negative. Now the depolarized stage becomes repolarized by the entry of potassium ions.
During depolarization, the potential of the cell is -55mV. When repolarization occurs, it is again -70mV. But the potassium channels are open and some of the potassium ions move out of the cell making the inside environment more negative. This is known as hyperpolarization condition.
This hyperpolarization remains for a short period where action potential can't occur. This period is called the refractory period. Again potassium ions enter into the cell. This results in the resting potential of the neuron again.
People have manipulated the genome of horses and ponies in the lab to produce the breeds we know today
They allow the section of dna to match up with the plasmid in the right position
