A teacher shows students a string of beads as a model of a chromosomes and genes. What do the beads represent? Explain

If the string of beads refer to a chromosome, then each bead is a gene responsible for one or more traits.

If the string of beads refer to a gene, then each bead refers to the sequence of nitrogenous bases in one strand of the gene.

Explanation:

A chromosome is composed of several genes.

A gene is composed of several nucleotides each containing a nitrogenous base. A gene is primarily made functional by the sequence of nitrogenous bases in its structure. If AGATTCA is a hypothetical sequence of the nitrogenous bases on one strand of a hypothetical gene then TCTAAGT will be the sequence of nitrogenous bases on the complementary strand of that particular gene.

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.

the answer is "a.) well–developed vascular system."

explanation: