The answer is A, a vaccine. This is why they are often given to children for prevention.
Eyeglasses<span> (also called spectacles) are</span><span> the most common form of </span>eye wear.<span> They are used to correct or improve many types of vision problems. They are a frame that holds two pieces of glass or plastic, which have been ground into lenses to correct refractive errors.</span>
Answer: in the process of polyspermy development
Explanation: in most cases the egg cell blocks polyspermy
Answer: Made mostly of collagen, bone is living, growing tissue. Collagen is a protein that provides a soft framework, and calcium phosphate is a mineral that adds strength and hardens the framework. This combination of collagen and calcium makes bone strong and flexible enough to withstand stress.