What is cell specialization and differation?

During an investigation of an xss attack, the investigator comes across the term "[a-za-z0-9\%]+" in analyzed evidence details. what is the expression used for?

Ialready know the answers to these questions and they are on the attachment. but i just need to know why that answer is the correct one. plz asap! this is for a report that i need to email by 10!

Ineed a little . why do you think there is a basic difference between the kinds of fertilization most common in aquatic and terrestrial animals?