<span>Genes.Genes are the working unit of the hereditary character of DNA. Genes act as instructions usually coding for a particular protein or function. One form of gene which are called alleles <span>determines the traits that can be passed on from parents to offspring.</span></span>
The main 'job' of the endocrine system in most animals is to moderate and send out chemicals that affect other organs, tissues, and organ systems of the body.
A. To solve problems... I think let me know if it helps
Both. You can use it as singular or plural.