BEST ANSWER WINS BRAINLIEST
When and where was the possibility of growing thornless varieties of plants discovered?

The discovery of thornless plants was made around the turn of the 20th century. to name one such thornless plant, particularly, the blackberry plant, the deviation from the  thorned blackberry canes were discovered in the united states. since then, several different thornless blackberry varieties have been cultivated for fruit gardens.

your answer is "the 1950's"

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.