There are two main theories for the lack of organic material in desert soils. Firstly, the organic life in most deserts is so sparse that it cannot produce much organic matter. Secondly when things do die and decompose in the desert the heat and sunlight often bleach nutrients out of the matter before it is decomposes enough to be absorbed into soil
Answer:
A biologist discovered a young, four-legged animal. The animal had lungs, seemed to fertilize internally, and its outer surface was covered with scales. In which class of animals is the biologist likely to place the animal?
reptile
Answer:
LD50 (median lethal dose)
Explanation:
- Whenever one needs to quantify the virulence of a pathogen then this is done by using a set of laboratory animals.
- LD50 (median lethal dose) is an important indicator of virulence.
- LD50 is defined as the number of pathogens that are required to kill 50% of the total infected animals.
- For the calculation of LD50, the animals are infected with a known number of pathogens and then a graph is plotted for the percentage of animals killed against the concentration of the pathogen used for infection.<em> The point at which the graph indicates the death of 50% animals, the corresponding concentration of inoculation of a pathogen is taken as the LD50 of that particular pathogen. </em>
Answer: a bowling ball ...
Explanation:
