The proteins in the cell membrane allow the nutrients to go and waste to go out <span>of a cell. Water passes through the cell membrane without the help of proteins.</span>
Arterias, venas y capilares.
Crossing over is important because it creates genetic variability.
<h3>What is crossing over?</h3>
It is the exchange of chromosomal segments between non-homologous chromosomes in a tetrad.
Since chromosomal segments contain genes at different loci, the exchange will increase the genetic variability of the new chromosomes.
Thus, the daughter cells carrying the recombined chromosomes will be genetically variable from not just the parent cell, but fellow daughter cells.
More on crossing over can be found here: brainly.com/question/19671756
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In the above food web green algae is the producer, periwinkle and microscopic animals are primary consumers; mussel, barnacle, dogwhelk and crab are secondary consumers; dogwhelk and crab comes under tertiary consumer; dogfish is a quaternary consumer.
What is a food web?
It is a natural interconnection of several food chains in a single ecosystem. Each food chain supplies energy and nutrients through the ecosystem. There are four food webs producer, herbivores, carnivores, omnivores and decomposers.
Here green algae comes under autotrophs(prepares their own food), periwinkle and microscopic animals are herbivores(depend on producer); mussel, barnacle, dogwhelk and crab are carnivores(depend on herbivore); dogfish is an omnivore(depends on both producer and carnivore).
Learn more about food web from the link given below:
brainly.com/question/2179?utm_source=android&utm_medium=share&utm_campaign=question
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