Answer:
recessive
Explanation:
A lethal allele is a gene variant associated with a mutation in an essential gene, which has the potential to cause the death of an individual. In general, lethal genes are recessive because these alleles do not cause death in heterozygous individuals, which have one copy of the normal allele and one copy of the allele for the lethal disease/disorder. In recessive lethal diseases, heterozygous individuals are carriers of the recessive lethal allele and can eventually pass the 'defective' allele on to offspring even though they are unaffected; whereas dominant lethal diseases are caused by dominant lethal alleles, which only need to be present in one copy to be fatal. In consequence, the frequency of recessive lethal alleles is generally higher than dominant lethal alleles because they can be masked in carrier individuals. Some examples of human diseases caused by recessive lethal alleles include, among others, Tay-Sachs disease, sickle-cell anemia, and cystic fibrosis.
Answer:
The answer is A) An element—An element can not be broken down chemically into a simpler substance
Groundwater supplies drinking water for 51% of the total U.S. population and 99% of the rural population. Groundwater helps grow our food 64% of groundwater is used for irrigation to grow crops. Groundwater is an important component in many industrial processes.
Although bacteria can be seen without staining, not all of their characteristics can be visible. Thus, with staining one can see if the bacteria is gram positive or negative, the outer wall's or capsule's structure, the exact size and texture of the surface etc. Without staining, it would be very difficult if not impossible to differentiate between different bacteria types.
Fixing a bacteria allows the scientist to immobilize and preserve it. Thus a complex study can be performed over a longer period of time. The bacteria can also be preserved in order to be restudied at a later date.
