The plasma membrane of the sea urchin egg has receptor molecules that are specific for binding acrosomal proteins .
<h3>What is plasma membrane ?</h3>
Plasma membrane is the outermost covering of the body which selectively permits the entry and exit of different type of materials .
Thus ,it is also called as selectively permeable membrane.it also separates the inner and outer environment of the cell .
It also helps in the diffusion process .
<h3>What are sea urchins ?</h3>
Sea urchins belongs to the animalia kingdom , Echinodermata Phylum, and Echinoidea class . they are small marine animals .Sea urchins are spiny , globular .
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Answer:
They are called Mygalomorphs.
Explanation:
<h2><u><em>
Brainliest Please!</em></u></h2>
Cell divison is necessary to replace cells that are worn and aging. Cells do not have an indefinite life span. Fo example, the life span of a red blood cell is about 120 days.
The smooth, but steady, increase in muscular tension produced by increasing the number of active motor units is called a recruitment.
Muscle tension is the force produced when a muscle contracts (or when sarcomeres shorten). The two primary forms of skeletal muscle contractions, isotonic contractions and isometric contractions, are produced when a muscle contracts against a load that is not moving.
- A load is transported as the length of the muscle varies during isotonic contractions, in which the tension in the muscle remains constant (shortens). Concentric and eccentric contractions are the two varieties of isotonic contractions.
- When a muscle contracts isometrically, the angle of a skeletal joint remains the same while tension is produced in the muscle. Sarcomeres shorten and muscles tense up during isometric contractions, but the load is not moved since the force generated is insufficient to overcome the resistance provided by the load.
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