Answer:
The correct answer is - autosomal codominant inheritance (due to multiple alleles).
Explanation:
Autosomal codominant inheritance or codominance is a pattern of inheritance where the alleles present of an autosomal gene express their character in the phenotype. In other words, in this type of pattern, no allele would be masked by other alleles and both will be expressed in the phenotype.
The human ABO blood group is an example of this pattern as there are three alleles A, B, and O. In the heterozygous case of AB blood group both A, and B alleles expressed together however, O is masked by both alleles A, and O.
Tree sap getting hardened
100,000,000 years ago there were mosquitoes like today and also like today they fed on the blood on animals. Namely dinosaurs
Sometimes after biting a dinosaur they’d land on a branch of a tree and get stuck in its sap
DDT stands for dichloro-diphenyl-trichloroethane. The first kind of synthetic/artificial insecticides came into use in the 1940s. The earlier usage of DDT include: a) Killing of malarial vectors, b) Combatting Typhus and other insect borne human diseases, c) As a pest control in crops d) as a pest control in garden, live stock production and even at homes.
The negative impact of DDT could be felt for the first time when the pests that were earlier killed by use of DDT have now become pesticides resistant. In the 1950s in USA, the regulatory measures were adopted to reduce the usage of DDTs as its effects as a pesticides were no more long significant and also it was creating detrimental physical and psychological impacts on the human and environment.
It was in 1972 that the U.S. Environmental Protection Agency cancelled the order for banning the usage of DDT based on the adverse impact it produced on the environment, human and other life forms. Since then continuous studies are being conducted to analyse the impact of DDTs. In some later years it was established that DDT is the cause of producing tumors in liver.
Some of the common negative impacts produced by DDT as per the U.S. Department of Agriculture :
a) The non destructive nature – DDT can not be destroyed and thus it remains persistent in the atmosphere
b) It attacks the tissues of living organisms especially the animals and humans ( fatty tissue)
c) It can penetrate the atmosphere to deeper extent.
Now as per the current stuation, The use of DDT is controlled and other alternatives of pest control organisms is being deduced. As per the treaty of Stockholm Convention on POPs (Persistent organic pollutants) , usage of DDT for malarial control is justified but it puts a restrictive use of DDT as pesticides in other areas.
