Explanation:
The Earth's geologic past is divided into hierarchical time periods. This hierarchy comprises eons, eras, times, epochs, and ages, from largest to smallest. The Cenozoic, Mesozoic, and Paleozoic Periods are the three main divisions of the Phanerozoic.
Answer:
(a)-Rills, and arroyos or gullies develop mainly during prolonged droughts.
Explanation:
Soil erosion is the process of erosion, transport and sedimentation of soil, subsoils and rocks as an effect of the action of erosive agents such as water, winds and living things. The process of disintegration of rock particles (called sediments) is caused by the action of weathering (a set of chemical, physical and biological processes that cause soil and rock wear).
About soil erosion, we can confirm that the following information is true:
- Grasses and other vegetation, windbreaks, and contour cropping will help reduce soil loss from cultivated lands.
- Soils form naturally by weathering; if protected from erosion, sound management can maintain or enhance their nutrient levels and textural characteristics.
Answer:
a) The genes present on separate chromosomes exhibit indepedent assortment.
b) The genotype of tall and purple flower parent= TTPp
The genotype of short and purple flower parent: ttPp
Explanation:
a) In a dihybrid cross, if the genes are present on the same chromosome, they will not exhibit independent assortment. The genes present on the same chromosome are called linked genes. Linked genes are inherited together. The absence of independent assortment of a linked gene gives more of parental types in F2 progeny. Therefore, if genes are not present on a separate chromosome, Mendel’s ratios deviate.
b) Alleles for tallness and purple flower are dominant. In the progeny, all the plants are tall. This means that the dominant tall plant is homozygous. With respect to flower color, the trait exhibits segregation of dominant and recessive alleles and both purple and white flower progeny are obtained. This makes both the plants heterozygous for the flower color gene.
The genotype of tall and purple flower parent= TTPp
The genotype of short and purple flower parent: ttPp