Reasonablity of evaluation methods in developed countries for Maths and Sci students Globally considering, in many (or maybe all) developing countries professors/lecturers in universities only take mid-term and final few-hour-exams to evaluate students' learning. In some (or maybe all) developed countries they evaluate students by some combination of three types of factors: 


written assignments, i.e. student have to do their research on the subject and gather the information, 
verbal assignments, i.e. like written assignment but presenting them as a seminar or the like to the class, 
(small percentage of mark for) few-hour-exams.


My questions are:


Each of the evaluation methods has its own pros and cons: Not all students can show that they have learned enough just in a few hours exam especially due to anxiety; and not all students do their assignment by themselves. Why do developed countries consider written assignments as a big percentage of marks that a student can get?
Are there universities follow the method of only written and verbal assignments and don't take exams at all, and those universities are high ranked and their degree despite their poor method of evaluation have a high validity? Which universities? 


Note that this question are just purely about Science and Mathematics degrees on BSc and (especially) MSc levels.     

Thank you.
Why do yo suppose that the deciding factor in how programs evaluate student is the economic development of the country? Unless you have evidence to suggest otherwise, I don't think it is reasonable to make sweeping generalizations and judgement about how science programs in developed and developing nations assess their students. Instead, whether a course emphasizes exams or not depends on the nature of the subject and the level of mastery the students possess. For example, for a calculus class, it is very likely that you will be graded on your ability to do computational problems in an exam setting, and few independent projects or presentations will be required. However, in a graduate level seminar course in biology, for example, your daily discussion participation in the class will be more important, because the professors are more interested in your ability to think rather than memorization.