(1) The varying number of muscle fibers that contract
<span>In most muscles, the number of muscle fibers in different motor units ranges from a few to hundreds. The nervous system can thus regulate the strength of contraction in a muscle by determining how many motor units are activated at a given instant and by selecting large or small motor unties to activate. </span>
some muscles are almost always partially contracted. In such muscles, the nervous system my alternate activation among the motor units, reducing the length of time any one set of fibers is contracted. Prolonged contraction can result in muscle fatigue due to the depletion of ATP and dissipation of ion gradients required for normal electrical signals.ing.
<span>(2) varying the rate at which muscle fibers are stimulated </span>
<span>single action potential produces a twitch lasting about 100 msec or less. If a second action potential arrives before the muscle fiber has completely relaxed, the two twitches add together, resulting in greater tension. Further summation occurs as the rate of stimulation increases. When the rate is so high that the muscle fiber cannot relax at all between stimuli, the twitches fuse into one smooth, sustained contraction called tetanus.</span>
Pseudoscientists try to explain that archaeological remains use evidence out of context. Pseudoscientific statements can not be proven and are based on erroneous reasoning. While scientists use the scientific method and base their hypotheses on objective evidence. Scientific claims can be proven.
Answer:
Eutrophication
Explanation:
Algal bloom:
Algal bloom is the overgrowth of algae in a marine or freshwater environment resulting in pungent odors and discoloration of water. Algal blooms arise in nutrient rich water due to a process called eutrophication.
Eutrophication is the presence of excess nutrients in water that promote the growth of algae and aquatic plants. This excessive growth results in the depletion of oxygen.
Eutrophication causes the build-up of inorganic chemicals such as ammonia, hydrogen sulphide and nitrites to a level that becomes toxic for fish and organisms. This coupled with depletion of oxygen kills fish resulting in the addition of more nutrients to the water.
Answer:
largest of the three, positive charge, inside nucleus
Explanation:
Answer:
Haploid cells are produced from two diploid cells.
Explanation:
Meiosis is defined as a division process in humans in which the diploid cells containing two sets of chromosomes divides to form haploid cells which contains only one set of chromosomes. A haploid cells in human are sperm and eggs.
During fertilization, the starting nucleus is always diploid and the nucei that result at the end of the meiotic cell division are haploid. The reduction in chromosome number is achieved because meiosis consists of one round of chromosome duplication and two round of nuclear division.