Natural selection would probably favor different varieties in the different islands. In other words, beaks changed as the birds developed different tastes for fruits, seeds, or insects picked from the ground or cacti (due to lack of food resources). Long, pointed beaks made some of them more fit for picking seeds out of cactus fruits.
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Answer:
The Elephant can be defined as a KEYSTONE SPECIE
Explanation:
A KEYSTONE SPECIE is an animal specie that maintains an ecosystem relative to their population. These species' activities, play a crucial role in maintaining the ecosystem. In this case, the elephant's activity of uprooting trees, helps in keeping the ecosystem in check, and support its current inhabitants.
The secondary cell wall is a structure found in many plant cells, located between the primary cell wall and the plasma membrane. The cell starts producing the secondary cell wall after the primary cell wall is complete and the cell has stopped expanding.
Secondary cell walls provide additional protection to cells and rigidity and strength to the larger plant. These walls are constructed of layered sheaths of cellulose microfibrils, wherein the fibers are in parallel within each layer. The inclusion of lignin makes the secondary cell wall less flexible and less permeable to water than the primary cell wall. In addition to making the walls more resistant to degradation, the hydrophobic nature of lignin within these tissues is essential for containing water within the vascular tissues that carry it throughout the plant.
The secondary cell wall consists primarily of cellulose, along with other polysaccharides, lignin, and glycoprotein. It sometimes consists of three distinct layers - S1, S2 and S3 - where the direction of the cellulose microfibrils differs between the layers.
The correct answer is a - silicon dioxide.
Diatoms are single celled algae. They have a silica - based cell wall called a frustule, which gives each diatom a particular shape.
Diatoms exist as separate single cells although some may be found in groups or colonies. The ones found in colonies create very pretty forms: leaf shaped, oval , star and even like a period.
Outer shells of diatoms are quite valuable. They are used in industry in the manufacture of toothpaste to give it grit.
Answer:
The correct answer is it will be pushed away from the source of the electric field.
Explanation:
An electric field contain two electrodes positive charged electrode or anode and negative charged electrode or cathode.These 2 electrodes cathode and anode are connected by an electric wire to a battery and this whole system is linked to a electric system.
When electric current is applied oxidation reaction occur in anode and reduction reaction occur in cathode.
Now according to the question if a positively charged object is placed within a positive electric field then pushes the positively charged object away from itself because we all know that positively charged ion reflect another positively charged ion.