To answer this question, subtract from the total population of 1000 the homozygous dominant (DD) frogs of 280 and the homozygous recessive (dd) frogs of 220, and you are left with 500 frogs that by default are <span>heterozygotes (dD). The frequency of these frogs would be 500/1000 = 0.5</span>
.Answer:
Option A, fix nitrogen inside nodules on the roots of legumes
Explanation:
Rizhobium bacteria live in symbiotic relationship with roots of leguminous plants such as pulses including alfalfa, soybean etc.
Rhizobium or Bradyrhizobium is a gram negative bacteria that satisfies the nitrogen starvation of host plant.
These bacteria get habitation and nutrition from these leguminous plants and in return they fix the nitrogen into the nodules of the roots. This is a kind of facultative association between soil bacteria rizhobium and legume plants.
Hence, option A is correct
Thus, option A is correct
Meiosis.
Meiosis gives crossing over genes causing the organism to have genetic variety