Why did it take so long for people to rediscover cave paintings ?

He fields of graphic design and animation changed completely in a very short period of time in the late twentieth century. nearly everything that was once drawn by hand on a drafting table is now done on a computer screen. what are some of the advantages of this transition to digital techniques? are there any disadvantages? what are some of the skills that today’s graphic designers and animation engineers have that earlier ones did not? are there any skills that have been lost in the move to digital techniques?

Organum was first developed by religious singers adding another melody directly above the chant and mirroring the chant line. true false

Need some ! asap i need to figure out 3 major changes in bridges over time and why these changes to adapt to both improvements in technology and changing social links would also alot.