Answer:
During the course of a continuous isometric contraction of given strength, the electrical activity progressively increases. This is due to recruitment of motor units taking place to compensate the decrease in force of contraction occurring in the fatigued muscle fibres.
Explanation:
Answer:
Which type of selection tends to increase genetic variation? A. Disruptive selection B. Directional selection C. Stabilizing selection
The Answer is option A (Disruptive selection)
Explanation:
Selection can either shift the mean value of a trait, reduce the trait's variation, or increase its variation.
Genetic variation which allows natural selection to increase or decrease frequency of alleles already in the population is a source of phenotypic variation as it refers to differences in all the hereditary information of members of the same species.
Disruptive Selection is important in maintaining variation and initiating speciation as it Increases Variation by favoring alleles corresponding to more extreme phenotypes. But for it to occur, the mean phenotype has to experience the lowest fitness. Disruptive selection affects the frequency distributions of alleles and genotypes within a population.
Disruptive selection is based on the variance of a trait in a population as it increases genetic variance by equalizing the frequencies of existing alleles at polymorphic loci (a genetic loci with two or more alleles). Disruptive selection maintains and may even increase variation in natural populations by favoring extreme phenotypes, individuals with extreme values for a trait have greater reproductive success than individuals with intermediate values.
Answer and explanation:
Epinephrine and norepinephrine are two hormones that are released from the adrenal medulla when the body is under stress (like during exercise, for example) as a part of the sympathetic response.
These hormones have many functions and they all work together to prepare the individual for a fight or flight response -<em> like increasing heart rate and producing bronchodilatation</em>. One of these functions is the rise of glucose levels in blood which is important for this substance to reach several tissues, like the skeletal muscle. The skeletal muscle will make use of this glucose to produce ATP and generate the required energy for muscle contraction through a process called glycolysis, which is key for the fight or flight response mentioned above.
When we exercise, glucose levels rise thanks to these hormones so the skeletal muscle can have enough energy to contract and move as we want. If the exercise is too intense or prolongued, glucose levels will drop and other fuels will be needed to sustain this activity, like stored glycogen and fat.
The correct answer would be B
Answer: B. It protects the inner organs
Explanation: For example, your ribs protect the lungs, heart, stomach, and more!
