What phenotypic ratio would you expect as a result of a test cross between a dihybrid organism and one that is homozygous recessive for alleles at two independent loci?
a. 3:1
b. 9:3:3:1
c. 1:1:1:1
d. 1:2:1
e. 9:4:2:1
Answer:
c. 1:1:1:1
Explanation:
When a heterozygous individual for two genes is test crossed with a double homozygous recessive individual, the progeny is obtained in 1:1:1:1 phenotypic ratio. This occurs as the heterozygous dominant individual forms four types of gametes in 1:1:1:1 ratio while the homozygous recessive individual would form only one type of gamete having one recessive allele for each gene.
For example, a test cross between TtRr (tall and red) and ttrr (short and white) would produce a progeny in following ratio=
1 tall, red: 1 tall, white: 1 short, red: 1 short, white
Here, T= tall, t= short, R= red, r= white
Over many years, the lynx populations separated by a river will likely experience phenotypic changes, with the northern population developing thicker coats due to colder weather. This change is a result of selective pressures and can lead to geographic variation known as a cline, possibly culminating in speciation.
The question asks about how two lynx populations, separated by a river, will differ in their coat thickness after many years due to different environmental conditions. The population on the north side of the river experiences much colder weather compared to the population on the south side. Over time, due to geographical variation and selective pressures from their respective environments, it is likely that the two lynx populations will exhibit phenotypic changes, such as variations in coat thickness.
These changes can be understood as a type of geographic variation known as a cline, where a species' characteristics gradually change across an ecological gradient. In this case, we would expect the population in the colder northern environment to develop thicker coats as an adaptation for better heat conservation, a trait that would be less advantageous for the population on the warmer southern side of the river. This adaptation is a result of the selective pressures imposed by the differing climates on either side of the river.
Over many years, the accumulation of these selective pressures can eventually lead to significant divergence between the two populations, potentially giving rise to speciation if the genetic differences become substantial enough to prevent interbreeding should the river barrier be removed.
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Answer: The northern Lynxes' will experience thicker coats over time, the southern Lynxes will experience no chance whatsoever.
Explanation: the northern lynxes live on the colder side so they will adapt to be more used to the environment. the southern lynxes will stay the same because the weather isn't that bad.
Options for the question have not been provided. The complete question has been attached.
Answer:
A. Yes, we will see growth. Yes, they will glow.
Explanation:
pGLO plasmid was engineered to be used as a vector in the field of biotechnology. It has an ampicillin resistance gene which acts as a reporter gene. It also has another reporter gene, GFP which shares its promoter (araC) with the gene responsible for metabolizing arabinose. GFP gene is thus translated only in the presence of arabinose in the medium since the promoter is active only in the presence of arabinose. Once the GFP gene is translated, the colonies glow with green fluorescence under UV light.
Here, the E.Coli colonies were grown successfully on LB + Ampicillin + Arabinose plate so they were ampicillin resistant. They also glowed in UV light. If these transformed colonies are inoculated in another LB + Ampicillin + Arabinose plate they will be able to grow successfully since they are ampicillin resistant. They will also glow because the new plate also has arabinose so the araC promoter will be active and expression of both GFP gene and arabinose metabolizing gene will occur.
Answer:
Explanation:
The index fossil is an example of evidence of unconformity. The statement given in the question if true.
Index fossils are the fossils used to define and identify the different geological periods. The fossils must have a short vertical range with a wide range of geographic distribution and the rapid evolutionary trends.
A fossil indicates the relative age of a rock in which it is found. Index fossils come from species that were widespread but existed for a short period of time.
An unconformity is a buried erosional surface which separates two rock masses or strata of different ages, indicating that the sediment deposition was not continuous. A geologic unconformity is when an older rock formation has been deformed or partially eroded before a younger rock layer, usually a sedimentary rock is laid down which results in mismatched rock layers.
Thus, index fossils can be used as an evidence of unconformity.
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Answer:
True
Explanation:
Answer:
grade 9 biology 2021 all chapter
Biology is a natural science that studies living organisms and their interactions with their environment. Living organisms are organized in a complex hierarchy and share key properties. Through time, less-diverse ancestral organisms evolved into the diverse life forms we see today.
Biology is the science that studies living organisms and their interactions with one another and their environments. This discipline attempts to describe and understand the nature of the universe in parts or as a whole. Biology is considered a natural science along with fields related to the physical world and its phenomena.
Living organisms share several key properties such as order, sensitivity or response to stimuli, reproduction, growth and development, regulation, homeostasis, and energy processing. They are organized in a hierarchy that includes atoms, molecules, organelles, cells, tissues, organs, and organ systems. Organisms, in turn, are grouped as populations, communities, ecosystems, and the biosphere.
This is further evidenced in a diagram called a phylogenetic tree that can be used to show evolutionary relationships among organisms. This indicates that the diversity of life today has evolved from less-diverse ancestral organisms over billions of years.
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It consists of different layers of different thicknesses.
It allows visible light to pass through completely.
It contains gases that filter out ultraviolet radiation.
2. Matthew has recently learned that Earth’s atmosphere is made up of nitrogen, oxygen, water vapor, and many other trace elements. Which of the following is NOT a way in which gases in the atmosphere are helpful to life on Earth?
Carbon dioxide insulates Earth
Protection against radiation from the Sun
Barrier against violent storms and lightning
Oxygen stays within the atmosphere
3. Which of the following is a way the atmosphere helps maintain life on Earth?
The atmosphere helps maintain a moderate temperature.
The atmosphere draws water vapor from outer space.
The atmosphere has air currents that rotate the planet.
The atmosphere contains some gases that are toxic.
keep her skin protected. She wonders what else the atmosphere does that she takes for granted each day. The atmosphere allows which of the following to happen?
Meteorites to hit Earth’s surface
Chloroplasts producing oxygen
Reflection from the ocean's surface
Precipitation and the water cycle
5. Gases in the atmosphere are helpful to life on Earth because they offer protection from which of the following?
Poisonous gases from stars
Harmful radiation from the Sun
Collisions with other planets
Violent storms and lightning
6. Without the atmosphere, life on Earth would not be possible. Which of the following is NOT an explanation for how Earth’s atmosphere protects life on the planet?
It allows visible light to pass through completely.
It contains gases that filter out ultraviolet radiation.
It keeps Earth warm by trapping in heat.
It protects life from ultraviolet rays of light.
7. Alexander applies sunscreen to help provide protection from ultraviolet radiation. With what does the atmosphere provide protection for Earth?
Thick layers of ice clouds
Ozone in the upper atmosphere
Water vapor in the lower atmosphere
The reflective surface of the ocean
8. The atmosphere is often referred to as a blanket that covers Earth, keeping out harmful things and protecting life inside. Which of the following best represents a way in which the atmosphere helps maintain life on Earth?
The atmosphere provides air for oxygen.
The atmosphere controls the distance from the Sun.
The atmosphere helps rotate the planet.
The atmosphere provides protection from disease.
9. Which two gases in the atmosphere are essential to life on Earth?
Nitrogen and helium
Carbon dioxide and oxygen
Neon and argon
Helium and hydrogen
10. The atmosphere is made up of four different layers: the thermosphere, mesosphere, stratosphere, and troposphere. Which of the following is NOT true regarding the composition and structure of the the atmosphere?
The structure maintains safety against harmful UV rays.
The composition allows necessary gases for life on Earth.
The atmosphere allows Earth to rotate around the Sun.
The atmosphere is made up of nitrogen, oxygen, and a variety of gases.
Earth's atmosphere contains gases that filter out ultraviolet radiation. So, the correct options for 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 are D, A, A, D, B, A, B, A, B and C respectively.
The layer of gases that covers the Earth is known as the atmosphere. It is made up of roughly 78% nitrogen, 21% oxygen, and 1% additional gases like argon, carbon dioxide, neon, and methane. It is held in place by the gravity of the Earth. The troposphere, stratosphere, mesosphere, and thermosphere are the four principal layers of the atmosphere.
Gases in the atmosphere of Earth serve as UV radiation filters. CO2 acts as an insulator. The existence of life on Earth is not a result of atmospheric gases. A temperate temperature is kept by the atmosphere. The water cycle and precipitation are made possible by the atmosphere. Life on Earth benefits from gases in the atmosphere because they provide protection from harmful solar radiation.
Earth is protected by ozone in the upper atmosphere. The best way to think about how the atmosphere supports life on Earth is as the source of oxygen in the air. The atmosphere's carbon dioxide and oxygen are necessary for life on Earth.
So, the correct options for 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 are D, A, A, D, B, A, B, A, B and C respectively.
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Answer:
i think 1. is d and 2. is c i hope it helps
Explanation: