The alula is a small structure that is found on birds. It is located at the joint between the hand wing and the arm wings of birds and it is the freely moving, first digit of a bird's wing. It is normally used by birds in slow flight. In humans, the structure that is comparable to the alula is the thumb.
Answer:
A. Calcium would be transported to the sarcoplasmic reticulum therefore contractions would cease.
Explanation:
A muscle fibre will stop contraction immediately ATP is used up. Also, muscle contraction will end as soon as the information from the motor neuron stops. This repolarizes the sarcolemma and T-tubules, thereby closing the voltage-gated calcium channels in the sarcoplasmic reticulum. Calcium ions are then pumped back into the sarcoplasmic reticulum, in order for tropomyosin to cover the binding sites on the actin strands again.
Explanation:
A mutation is made once in every <u>10 billion</u> nucleotides copied.
During the process of cell division, spontaneous changes within the genome can arise. These mutations are errors occur when copies of the DNA within the cell are made; mutations may range from small changes called single nucleotide polymorphisms, to large scale deletions, and additions which span multiple genes.
Further Explanation:
During reproduction other events, such as crossing over during mitosis and meiosis, mutations lead to increases in genetic variation. This variation refers to the genetic characteristics present within a species. Mutations may be either beneficial or deleterious; they are maintained within cells, as they form new traits called alleles. Beneficial mutations may confer traits that increase the fitness of a species, along with ensuring survival by conferring a protective advantage- these phenotypic differences between organisms are called adaptations.
Sequences of DNA make up genes which can have different forms called alleles. DNA, which makes up the genotype, is transcribed into mRNA and later translated into amino acids which are linked together by rRNA to form proteins which make up the phenotype of an organism. Mutations in DNA sequences affect the corresponding mRNA and thus the protein encoded.
Learn more about mutations at brainly.com/question/4602376
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Commensalism<span>, in </span>ecology<span>, is a class of relationships between two organisms where one organism benefits from the other without affecting it. This is in contrast with </span>mutualism<span>, in which both organisms benefit from each other, </span>amensalism<span>, where one is harmed while the other is unaffected, and </span>parasitism<span>, where one benefits while the other is harmed.</span>