Which type of cell does not contain a nucleus enabling it to carry more hemoglobin?

leucocyte
white blood cell
nerve cell
erythrocyte

erythrocytes

Erythrocytes also called as red blood cells. These are the cells which does not possess nucleus. They exhibit a pigment named as hemoglobin, the heme  component of the hemoglobin has affinity for oxygen. It carries oxygen to all the parts of the body.

Initially the red blood cells are produced in the bone marrow with a nucleus. These red blood cells undergoes a process called as enucleation, this results in the removal of the nucleus from the cells. This process occurs when the cells attains maturity. It is a kind of adaptation that occurs in the red blood cells.  It allows red blood cells to carry more hemoglobin, thereby carrying more oxygen molecules. It allows the cells to have distinctively bi- concave shape, which facilitates diffusion of carbon dioxide and oxygen. This could not be possible in the presence of nucleus.

the real answer is b. scintillation counter

as the gila monster consumes the eggs or young of the desert cottontail and gambel's quail, thus its main food supply is only accessible for a restricted time duration every year. however, for this, the gila monsters exhibit three adaptations, which elevate their survival rate in the desert condition.  

first, is that they possess huge bodies, and can consume greater concentrations of food during a small period. secondly, they require to feed infrequently as they can accumulate fat in their tails. ultimately, their rate of metabolism is very low, so that they can burn their reservoirs of fat gradually.