<h2>Densities </h2>
Explanation:
The force which is responsible for an object to float over a liquid is the buoyancy force and it depends on the density of the liquid and the object which means that the object’s density should be less compared to the liquid density to float over the water
In case of birds such as ducks, geese, and swans, they have greater densities than water, yet they are able to sit on its surface because they have special glands which secretes oil
The secretion of oil makes their feathers oily and hence they can shed the water on feathers and feathers in turn do not get wet
These birds can then float easily on water by their webbed feet and larger surface tension of water
Surface tension is the elastic tendency of the surface of the fluid that makes it acquire the least surface area possible
Answer:
There are about 320,000 species of plants
Explanation:
approximately 13,000 known genera and 300,000 known species
To fully understand the processes occurring in present-day living cells, we need to consider how they arose in evolution. The most fundamental of all such problems is the expression of hereditary information, which today requires extraordinarily complex machinery and proceeds from DNA to protein through an RNA intermediate. How did this machinery arise? One view is that an RNA world existed on Earth before modern cells arose (Figure 6-91). According to this hypothesis, RNA stored both genetic information and catalyzed the chemical reactions in primitive cells. Only later in evolutionary time did DNA take over as the genetic material and proteins become the major catalyst and structural component of cells. If this idea is correct, then the transition out of the RNA world was never complete; as we have seen in this chapter, RNA still catalyzes several fundamental reactions in modern-day cells, which can be viewed as molecular fossils of an earlier world.
Plant obtain energy through photosynthesis .They are producers because they are able to obtain synthesize their food
Answer:
This change in skin color provides evidence that the environment can influence gene action.
Explanation:
Many studies have revealed that the physical traits of a person are attributed to the genetic makeup as well as the environmental characteristics. Some traits depend on both the factors. Environmental factors can determine which genes would be turned on or off or it might control the expression rate of a gene. For example, two identical twins might have different skin colour if one works in sunlight and the other works indoors.
