Answer:
True
Explanation:
Both Mercury and Bromine exist in the liquid state at room temperature.
This is Russia we're talking about, so there are bound to be a few minor extremes between seasonal temperatures.
Winters last fron November to March and are usually very cold. Temperatures often drop below freezing.
Summers are from May to August and are usually at a comfortable 70-80 degree range. Heatwaves can raise temperatures up to above 86 degrees.
Answer:
Option A
Explanation:
Option A shows the smallest building block of a living cell.
Answer:
Mass Number and Atomic Number
Explanation:
Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms or 'decays' into a different atomic nucleus, with a mass number that is reduced by four and an atomic number that is reduced by two.
Answer:
AaBb × aabb
Explanation:
A test cross is a cross between an unknown genotype (dominant phenotype) with a homozygous recessive genotype in order to discover the actual genotype of the species exhibiting dominant phenotype.
This is because one allele of a gene is capable of masking the expression of another, the allele masking is called DOMINANT allele while the allele being masked is called RECESSIVE allele. The combination of these two alleles is termed heterozygosity.
An organism that is phenotypically dominant for a specific trait may either be heterozygous or homozygous for that gene. For example, a plant gene for tallness with an dominant allele T, and recessive allele t. This plant will need tall if the genotype is TT (homozygous dominant) or Tt (heterozygous dominant). In order to know which of these genotypes the plant actually has, a test cross is conducted.
In this example, two genes A and B are involved. For the first gene, A represents dominant allele while a represents recessive allele. For the second gene, B represents dominant allele while b represents recessive allele.
In a cross involving parents AABB (homozygous dominant for both genes) and aabb (homozygous recessive for both genes), the F1 progeny will all exhibit phenotypic dominance (AaBb).
However, we cannot know the genotype by merely looking at the phenotype. We cannot ascertain yet whether the dominance is heterozygous or homozygous, hence the need for a test cross.
The test cross is between the dominant F1 progeny and a homozygous recessive i.e. AaBb × aabb. Some of the F2 generation will show recessive traits if the unknown genotype is heterozygous.
