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4 years ago

What caused the decrease in the global human population in 1400?

Biology

1 answer:

Alinara [238K]4 years ago

4 0

Answer:

Pandemic plague

Explanation:

The Black death or the Great Plague occured during 1347 to 1351 in Eurasia causing death of almost 75 million to 200 million people. The cause of this plague was identified a bacterium known as Yersinia pestis . This plague outbreak was first major European plague pandemic and it killed almost 30% to 60% population of the Europe.

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Link the digestive and the breathing system to respiration and how the products of aerobic respiration and anaerobic respiration

UNO [17]

When food is digested, the food is broken down into Glucose, which can get into the bloodstream through the small intestines. It travels around the body in the bloods plasma and is then diffused into the body's cells through the capillaries. Once the Glucose is in the body cells, it can be used for respiration.
The breathing system is used in respiration because we need it to respire aerobically, so that our body gets all the vital oxygen it needs. When we breathe, oxygen is stored in the alveoli in the lungs. From there, it can be diffused into the bloodstream, to be used for respiration.

The products of aerobic respiration is Carbon Dioxide and Water. The Water leaves the body as sweat or waste such as urine. The Carbon Dioxide is carried through the blood to our lungs where we can breathe it out. Where as in anaerobic respiration, the product is Lactic Acid. This ends up being broken by oxygen after exercise (oxygen debt) and is also turned into Carbon Dioxide and Water.

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4 years ago

Changing geographic distribution of disease vectors meaning

zhuklara [117]

Answer:

Vector changes with geography.

Explanation:

Vectors of disease are changing with the changing in the geographic location because different vectors survives in different environment so due to change in geography, vectors of a disease also change. Vectors refers to organisms that is responsible for carrying infectious bacteria or viruses that causes certain diseases in animals, plants and humans. Different vectors are present in different geography due to different climatic condition that forbit one vector to survive in all environments.

6 0

3 years ago

If two genes are found on different chromosomes, or if they are far enough apart on the same chromosome that the chance of a cro

nika2105 [10]

Complete question:

A wild-type tomato plant (Plant 1) is homozygous dominant for three traits: solid leaves (MM), normal height (DD), and smooth skin (PP).

Another tomato plant (Plant 2) is homozygous recessive for the same three traits: mottled leaves (mm), dwarf height(dd), and peach skin (pp).

In a cross between these two plants (MMDDPP x mmddpp), all offspring in the F1 generation are wild type and heterozygous for all three traits(MmDdPp).

Now suppose you perform a testcross on one of the F1plants (MmDdPp x mmddpp). The F2 generation can include plants with these eight possible phenotypes:

solid, normal, smooth

solid, normal, peach

solid, dwarf, smooth

solid, dwarf, peach

mottled, normal, smooth

mottled, normal, peach

mottled, dwarf, smooth

mottled, dwarf, peach

Assuming that the three genes undergo independent assortment, predict the phenotypic ratio of the offspring in the F2 generation.

Answer and Explanation:

Cross 1:

Parental) MMDDPP x mmddpp

F1) MmDdPp

Cross 2: Testcross

Parental) MmDdPp x mmddpp

Gametes) MDP MdP MDp Mdp mDP mdP mDp mdp

mdp mdp mdp mdp mdp mdp mdp mdp

Punnet Square)

mdp

MDP MmDdPp

MdP MmddPp

MDp MmDdpp

Mdp Mmddpp

mDP mmDdPp

mdP mmddPp

mDp mmDdpp

mdp mmddpp

F2) 8/64 = 1/8 MmDdPp, solid leaves, normal height, smooth skin

8/64 = 1/8 MmddPp, solid leaves, dwarf height, smooth skin

8/64 = 1/8 MmDdpp, solid leaves, normal height, peach skin

8/64 = 1/8 Mmddpp, solid leaves, dwarf height, peach skin

8/64 = 1/8 mmDdPp, mottled leaves, normal height, smooth skin

8/64 = 1/8 mmddPp, mottled leaves, dwarf height, smooth skin

8/64 = 1/8 mmDdpp, mottled leaves, normal height, peach skin

8/64 = 1/8 mmddpp, mottled leaves, dwarf height, peach skin

Another way of predicting the phenotypic ratio of the offspring in the F2 generation is by performing a testcross for each gene by separately and then multiplying their genotypic proportions. This is:

Leaves Gene

Parental) Mm x mm

Gamtes) M m m m

Punnet Square) M m

m Mm mm

F2) 1/2 Mm

1/2 mm

High Gene

Parental) Dd x dd

Gamtes) D d d d

Punnet Square) D d

d Dd dd

F2) 1/2 Dd

1/2 dd

Skin Gene

Parental) Pp x pp

Gamtes) P p p p

Punnet Square) P p

p Pp pp

F2) 1/2 Pp

1/2 pp

To get the phenotypic ratio of the offspring we multiply the genotypic proportion for each trait by the genotypic proportions of the other two traits, like this:

For plants with solid leaves, normal height, smooth skin

solid leaves ratio -> 1/2

normal height ratio -> 1/2

smooth skin ratio -> 1/2

MmDdPp ratio: 1/2 x 1/2 x 1/2 = 1/8

For plants with solid leaves, dwarf height, smooth skin

MmddPp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with solid leaves, normal height, peach skin

MmDdpp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with solid leaves, dwarf height, peach skin

Mmddpp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with mottled leaves, normal height, smooth skin

mmDdPp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with mottled leaves, dwarf height, smooth skin

mmddPp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with mottled leaves, normal height, peach skin

mmDdpp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

For plants with mottled leaves, dwarf height, peach skin

mmddpp ratio: 1/2 x 1/2 x 1/2 x 1/2 = 1/8

3 0

3 years ago

If the Velocity increases, the discharge would ___?

Liula [17]

Discharge is the act of removing or losing charge. If the velocity increases, the discharge would increase (i'm guessing that the width and depth of the area is increasing).

5 0

3 years ago

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Two difference between drone bee and worker bee

Ludmilka [50]

Answer:

The worker bees are female, but they do not breed. The queen bee is female and creates all the babies for the hive. The drone bees are male and do not have a sting. Bees communicate with each other about food sources using dances.

Explanation:

7 0

3 years ago

Read 2 more answers