Gravity , Explosion
<u>Explanation:</u>
Nebulae are made of dust and gases—mostly hydrogen and helium. The dust and gases in a nebula are very spread out, but gravity can slowly begin to pull together clumps of dust and gas. As these clumps get bigger and bigger, their gravity gets stronger and stronger.
Eventually, the clump of dust and gas gets so big that it collapses from its own gravity. The collapse causes the material at the center of the cloud to heat up-and this hot core is the beginning of a star.
The answer is ‘behavioral isolation’. It is a form of
sympatric speciation - which occurs even when
species live in the same habitat. In this case,
the individuals in the population are isolated by differences in mating and probably different mating rituals.
Answer:
Symbiosis or Mutualism: When two species live together in a close association that is helpful to both species, the relationship is known as symbiosis. The oxpecker bird and the rhinoceros exhibit this relationship. The oxpecker receives protection and obtains food from the ticks and other pests infesting the rhino’s skin.
Explanation:
Answer:
B. stomata.
Explanation:
Stomata are openings in the surface of the plant epidermis through which gases and water vapor pass. They are formed by two elongated cells whose shape is similar to bean grain or dumbbell depending on the species. These cells are called guard cells, and in their midst there is a slit called the ostiole.
The stomata make the exchanges between the external and internal environment of the plant. They regulate the size of the opening, so it is possible to increase or decrease the rate of perspiration of the plant.
Stomata are usually located at the bottom of the leaf, but in aquatic plants such as the water lily they are at the top and still in vertical growing plants on both sides.
