Last question, please help on biology??

Question

Explain the importance of an arthropod’s exoskeleton. In your explanation, be sure to address how is it able to grow tens of times larger than it was at birth, even though it has an exoskeleton. Also discuss at least two benefits of an exoskeleton as well as how the arthropod grows without compromising this skeletal system.

Answer 1

The arthropods constitute the most successful and diverse form of life on Earth, constituting millions of species in a diverse range of habitats, and varying in size from microscopic to quite large.

The name "arthropod" comes from the Greek, arthros jointed, and podes, feet.  Hence, jointed feet.  All arthropods possess a jointed rigid exoskeleton, which both supports the musculature and protects the animal.  The exoskeleton is formed by the cuticle, a protective layer composed mostly of chitin, long chained molecules of the sugar acetyl glucosamine, which when cross-linked form tough fibers embedded in a protein matrix

As the animal grows it has to shed its exoskeleton at regular intervals, a process known as molting.  During this time it is vulnerable to predators and disease, and also to desiccation if it is a  terrestrial form like an insect or spider.  Because the larger the animal the longer it takes for the new molt to harden, and hence the longer the time it is vulnerable, this process imposes limits on the size arthropods grow to.  Another limit with terrestrial forms like insects is that breathing is through pores in the side of the body.  Hence arthropods are mostly small, even microscopic, with very few growing to giant size.  Science fiction giant ants and the rest are simply physiologically impossible (though that never stopped sci fi writers in the past).