Can someone ?
4. which of the following statements regarding human genetic disorders is accurate?
a. disorders in individual genes are responsible for down's syndrome.
b. nondisjunction is responsible for causing huntington's disease.
c. disorders in individual genes can cause disease or provide individuals with a genetic advantage.
d. nondisjunction can lead to an incorrect number of sex chromosomes.

white blood cells or wbc s are mainly 2 types-

1.agranulocytes

2.granulocytes

the monocytes or macrophages of agranulocytes , dendritic cells which are accessory leucocytes, and b cells which is one type of lymphocytes   identify the antigens present on the pathogen's surface. these three cells are called antigen presenting cells(apc) which are phagocytes and destroy the antigens by secreting antitoxins. besides this leukocyte is always plays vital role in the immunity of the body.

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.