<em>sieve tube elements are the cells of phloem which allow transportation of photosynthates through phloem...
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how sieve tube elements form sieve tubes:
</u>sieve tube elements are connected end to end and form a long chain which is called sieve tube,,,,
sieve tube elements are connected with the help of a side chain with the help of peptide bond...also one element has tapering end which easily overlaps with other end of next element to form sieve tube,,,,</em>
Answer:
the answer is genetic drifts.
Answer:
The UN projects that the global population increases from a population of 7.7 billion in 2019 to 10.9 billion by the end of the century. By that time, the UN projects, fast global population growth will come to an end.
Beneath the global level, there are of course, big differences between different world regions and countries. While in some regions the world population will likely grow rapidly for the coming decades other regions will continue to see declining population numbers.
Global population growth is determined by the number of births and deaths. Improving health is increasing the size of the population as it is decreasing mortality. The countervailing trend are falling fertility rates – the trend of couples having fewer children is what brought rapid population growth to an end in many countries already, and what will bring an end to rapid population growth globally.
The global population growth rate has already slowed down considerably: It reached its peak at over 2% in the late 1960s and has been falling since.
The UN projections for the global population growth rates, which have been produced since the 1950s, have a good track record in projecting the size of the global population.
While the UN projections are most widely know there are other very carefully produced projections. The demographers of WC-IIASA model what will happen according to different scenarios and make clear that the population growth rate tomorrow depends on what we do today. Rapid progress in getting children and especially girls into schools will result in a much smaller global population.
The biggest disagreement between different projections is concerning the future of Africa. While the UN projects a 3.5-fold increase of the population of Africa, other researchers find a much smaller increase more likely.
Explanation:
here try this
Answer:
Classification change over time based on newly gathered information on species in order to accommodate them, such as molecular information about a species.
The following statements apply to autotrophs only:
1. Make their own food.
2. Use inorganic materials to produce energy.
3. Producers.
4. Many use photosynthesis to produce organic compounds.
The following statements apply to heterotrophs only:
1. Consumers.
2.Rely on other organisms for energy.
3. Unable to produce organic compounds from inorganic materials.
4. Obtain their food by consuming other organisms.
Generally, autotrophs are plants, which are capable of trapping the energy of the sun to produce their own food. That is why they are called producers. They have the capacity to produce organic compounds using inorganic raw materials. Other living organisms depend on the foods produced by autotrophs. The heterotrophs do not have the capacity to produce their own foods so they depend on the food produce by autotrophs, they also feed on other living organisms. That is why they are called consumers. <span />
