16. (08.05 mc) which of the following changes in modern agriculture challenges the validity of von thünen's theory? (3 points) i. increased consumer demand for organic food ii. decreased transportation time from farm to market iii. global demand for certain crops iv. increased mechanization of agriculture has increased crop yields i and ii i and iii i and iv ii and iii ii and iv

The answer is II and IV. Von Thunen's Theory 's proncipal variable is distance. If the crop field is close to the consumption area (a city), the cost of that land will be expensive. If it is far away, the cost of the land will reduce but the transportaions ones will increase. With the improvement of transportation the distance won't be such a determinant factor, those costs reduce considerably.

With the improvement of crop yields, wich Von THunen did not had in consideration, a single crop can provide a lot of food making the cost of the land reduce its importance.

the french revolution was when many people were persecuted for disagreeing or making separate government

after a more than a decade and a half of combating al qaeda (aq) in afghanistan and pakistan,

the united states faces a diverse array of threats from al qaeda affiliates in the middle east and

africa. while senior al qaeda figures reportedly remain based in pakistan, the network includes

a number of affiliates across the middle east and africa including al qaeda in the arabian

peninsula (aqap), al qaeda in the islamic maghreb (aqim), and al shabaab. al qaeda also

retains a small but possibly growing presence in afghanistan. u.s. officials have stated that al

qaeda still maintains a foothold in syria through its ties to hay’at tahrir al sham (formerly

known as the nusra front), though the exact nature of that relationship may be evolving. this

report examines the threat posed by al qaeda affiliates in the middle east and africa as described

by u.s. officials and outside observers, as well as the u.s. approach to date in responding to these

threats. this was all i could find hope this : )