Answer:
Microtubules
Explanation:
These filament-like structures are a major component of the cytoskeleton of the cell and help is maintain asymmetrical cell shape. They are composed of tubulin molecules arranged to form a 'hollow straw' attached to the cell membrane end to end . The contraction and lengthening of these microtubules are controlled by the addition of removal these of tubulin molecules to vary its length.
Basically certain traits are going to give a better outcome for the animal the white rabbits living on white snow are going to be able to survive better than the brown rabbit and the population of brown rabbits will be reflected through the graph
We first have to understand what a vascular system is. A vascular system consists of the water-carrying tube(xylem) and food-carrying tube(phloem). These 2 tubes are very essential for plants to survive. The xylem transports water to the leaves thru the stem to nourish the leaves so as to make food. The word equation is : Water + Carbon dioxide ----> Glucose + Oxygen. The phloem on the other hand transports the food from the leaves that creates them amd sent them to all parts of the plant. It is often a misconception that food is only sent to the fruits. The plant receives nutrition from the food that is made by the leaves. Overall the vascular system plays a very importamt roles in the survival of the plant.
To put it simple, think of the vascular system of a plant like the circulatory system of a human. Without the circulatory system, the human is unable to receive oxygen for breathing and remove carbon dioxide which is acidic in nature and pose a threat to the human body.
Natural selection<span> is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.</span>
Answer:
Elliptical galaxies, such as M87 have very little gas and dust. ... Both the largest and the smallest known galaxies are elliptical. Very large elliptical galaxies can reach 300 million light years in diameter. Dwarf ellipticals, which are very common, may contain only 1/100,000th as many stars as the Milky Way!
Most spiral galaxies contain a central bulge surrounded by a flat, rotating disk of stars. The bulge in the center is made up of older, dimmer stars, and is thought to contain a supermassive black hole. Approximately two-thirds of spiral galaxies also contain a bar structure through their center, as does the Milky Way.
