All of the following statements regarding dual x-ray absorptiometry are true, except
1. radiation dose is considerable.
2. two x-ray photon energies are used.
3. photon attenuation by bone is calculated.

Option (1).

Explanation:

Dual x-ray absorptiometry technique is used for the evaluation of the bone mineral density. The bone densitometry is normally used in this technique to estimate the mineral content of bone.

The radiation dose in the absorptiometry is considerable and only small or low amount of radiation dose is considered. The heavy dose may cause health problems in the individual. The photon energies are used for the bone and soft tissue. The treatment of osteoporesis can be done by this technique.

Thus, the correct answer is option (1).

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.