Answer:
Deep zone, surface zone and transition zone.
Explanation:
Open sea zone is the area of the coastal areas above the sea bed and cover the continental shelf where large Marine organism are present and there is enough sunlight algae organism use to photosynthesize and produce food for the Marine organisms by converting carbondioxide and water into carbohydrates.
The zone stretches from the surface , to the middle and depth of 200 m.
The surface zone is the area where light penetrates most , the transition stretches from the surface zone downward, in this zone light penetrates bit not as much as surface zone and in the deep zone, it stretches from the transition zone downward to a depth of 200 meters and don't have enough light penetration compare to surface and transition.
<span>The oldest known vascular plants in the northern hemisphere are Devonian
This is true</span>
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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Answer:
The correct option is b
Explanation:
Phospholipids are lipids that contains a phosphate group, which forms the "head" of the molecule and is hydrophilic (water loving). The "tail" of phospholipids is made of two fatty acids which are hydrophobic (water fearing). The phospholipid in the cell membrane acts as a selectively permeable barrier that regulates what goes in and out of the cell <u>thereby protecting the cell from some external molecules and ions</u>.
Planaria<span> can be </span>cut<span> into pieces, and each piece can </span>regenerate<span> into a complete organism. crazy huh</span>