1. which of the following advances in food production were attributed to the green revolution of the 1960s and 1970s? 2. which of the following factors contributed to the great famine in ireland in the mid-nineteenth century? 3. what happens to the food supply when food prices are high? 4. which continent has the highest proportion of food-insecure people? 5. what is the most likely effect that a war might have on food security?

1. drought-resistant varieties of crop plants

2. plant disease

3. The food supply gets shifted from the poor to the wealthy.

4. Africa

5. Crops would be burned and convoys attacked to deny food sources to the enemy.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation: