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3 years ago

Why is the Aral Sea shrinking

1 answer:

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It was how fast it was disappearing. Once the world's fourth largest lake, the Aral Sea in Central Asia has been losing water for half a century — ever since Soviet engineers began diverting the two rivers that sustain it, the Amu Darya and Syr Darya, in order to grow cotton in the desert.

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Describe the vascular system of plants. Include brief descriptions of the characteristics and function of xylem and phloem.

solong [7]

Answer:

The vascular tissue of the plants distributes water and nutrients, which guarantees a constant growth. Each newly formed cell needs to become the corresponding cell type in vascular tissue.

Explanation:

Like animals, plants need water and nutrients. While animals use a circulatory and digestive system to obtain and distribute nutrients, plants use a vascular system. This system absorbs water, vitamins and minerals from the soil and then transmits energy in the form of carbohydrates to the roots. The main components of the vascular system are the xylem and the phloem.

Xylem is a complex tissue formed by several cell types. Its function is the conduction of water and minerals from the root to the leaves. Among the cells that form this complex tissue differ:

- Conductive cells or tracheal elements: they are dead elements at maturity, they serve for vertical conduction and support

- Vessel members are observed in Angiosperms, the largest plant group with the most recent evolution; They are short, wide cells with thick secondary walls, they differ from tracheids because they are perforated elements.

- Storage elements: parenchymal cells, thick walls, secondary, can present crystals and other cellular contents.

- Support elements: fibers in the Angiosperms and fibrotracheids in Gymnosperms, elements of intermediate characters between the fibers and the tracheids.

Phloem cells conduct food (photosynthesis produced by photosynthesis) from the leaves to the rest of the plant. They are living cells at maturity and in histological preparations colored with Astrablue take the color blue. Phloem cells are located outside the xylem.

The sieve elements of this tissue are: the sieve cells in the Gymnosperms and the members of sieve tubes with their respective accompanying cells in the Angiosperms. The accompanying cells retain their nuclei and control the neighboring sieve tubes. Dissolved food, such as sucrose, circulates through the screened areas that connect these cells to each other.

Being a complex tissue, it also has parenchymal cells for storage and fibers and sclereids as a support.

4 0

4 years ago

White blood cells left in the body after an infection that help protect against future infection are called _______. Select one:

Semmy [17]

C. B cells
B cells make antibodies

7 0

3 years ago

A scientists wishes to determine whether or not a marine ecosystem underwent primary or secondary succession in the past. What e

Triss [41]

I believe the correct answer from the choices listed above is the second option. The evidence that would be most useful for making this determination would be to use radiocarbon dating to determine the age of the rock underlying the ecosystem.. Succession is usually initiated by a significant disturbance of an existing community. Hope this answers the question.

7 0

4 years ago

If a DNA strand contains the sequence 5Ê¹-ATTCCGGATCGA-3Ê¹, which of the following is the sequence of the complementary strand o

Svetllana [295]

Answer:

5Ê¹-ATTCCGGATCGA-3Ê¹

Explanation:

In a double-stranded DNA, two strands are held together with the help of hydrogen bonds between nitrogenous bases and the two strands are anti-parallel, means one strands runs in 5' to 3' direction, while another strand runs in 3' to 5' direction.

According to complementary base pairing rule, adenine makes bonds with thymine and thymine makes bond with adenine; similarly, guanine makes bonds with cytosine and cytosine makes bonds with guanine.

Thus, the complementary base pairing rule, complementary sequence for given DNA sequence would be:

5Ê¹-TCGATCCGGAAT-3Ê¹

3Ê¹-AGCTAGGCCTTA-5Ê¹, which can be also written as

5Ê¹-ATTCCGGATCGA-3Ê¹.

Thus, the correct answer is 'second option.'

7 0

3 years ago

Read 2 more answers

You just watched the animation, "Recognizing Primate Morphology," which demonstrates several traits that are characteristic of t

DiKsa [7]

Answer:

The best answer to the question: These characteristics make primates particularly well adapted to what type of environment? Would be: the arboreal environment.

Explanation:

According to the video, primates, which subdivide into several groups, including the apes, from which also humans evolve, have, depending on their group, specific anatomical features and traits that allow them to survive in their environment. One such anatomical trait is the presence of larger brains than other mammals, long limbs, long fingers and strong lower limbs that allow them to adapt to tree life and survive in forest regions. Also, they tend to have a much more acute sense of vision due to their larger brain, but a much more limited sense of smell than other mammals. These characteristics become basic for them to live and survive in forest environments.

7 0

3 years ago