The use of genetics by farmers to produce more abundant and healthier crops is an application of the science

biogenetic engineering
dna profiling
biotechnology
nuclear genetics

Biogenetic engineering

Explanation:

Biogenetic engineering is the correct option. This is because of the fact that here the farmers are using the knowledge of genetics, which means they are inserting the genes to the genome of the plants which allows them to produce traits which helps them to increase their yield, protect them against the environmental calamities such as drought, excess rainfall and pests. This is only possible in the case of application of science called as biogenetic engineering.  

x would be the most and the least would be y because there are more fruit   and seeds than flock z has insects

the supermassive black hole is in the middle of the galaxy.