Heterozygous is a term used in genetics to describe when two variations of a gene (known as alleles) are paired at the same location (locus) on a chromosome. By contrast, homozygous is when there are two copies of the same allele at the same locus.
The term heterozygous is derived from "hetero-" meaning different and "-zygous" meaning related to a fertilized egg (zygote).
Determining Traits
Humans are called diploid organisms because they have two alleles at each locus, with one allele inherited from each parent. The specific pairing of alleles translates to variations in an individual’s genetic traits.
An allele can either be dominant or recessive. Dominant alleles are those that express a trait even if there is only one copy. Recessive alleles can only express themselves if there are two copies.
One such example is brown eyes (which is dominant) and blue eyes (which is recessive). If the alleles are heterozygous, the dominant allele would express itself over the recessive allele, resulting in brown eyes. At the same time, the person would be considered a "carrier" of the recessive allele, meaning that the blue eye allele could be passed to offspring even if that person has brown eyes.
Alleles can also be incompletely dominant, an intermediate form of inheritance where neither
Answer:
Option B, Mammals and reptiles in the post-dinosaur age.
Explanation:
Adaptive radiation is mechanism through which species evolve very fast from common single ancestors. In simple words two different species are said to have evolved through adaptive radiation when they have descended from a single lineage. This is not the case with mammals and reptiles.
Generally in adaptive radiation, a species evolve when it faces new environmental challenges due to change of habitat or area. For example mammals have evolved from dinosaurs.
Hence, option B is correct
Edwin Hubble used the Doppler effect to determine that the universe is expanding. After years of scientific research and observation of different celestial bodies through a telescope, Hubble found that the light from distant galaxies was shifted towards the red end of the spectrum. This red shift indicates that stars are moving away from us and from each other. This phenomenon is called the 'expansion of the universe', also known as the big band theory.
B. mass extinctions happen when populations crash due to overpopulation while background extinctions are more likely to result from disease.
World formula
6CO2(gas)+12H2O(liquid)+photons------------------------->C6H12O6(aqueous)+6O2(gas)+6H2O
carbon dioxide+ water+light energy-->glucose+oxygen+water
