Answer:
(2) low power: 100 small pollen grains
high power: 25 large pollen grains
Explanation:
Compound light microscopes are devices used to greatly magnify objects. They have several objective lenses, a low-power lens magnifies 10 times (10X) the objects, and the high-power lens magnifies them 40 times (40X).
For that reason, when observing the pollen grains with the high-power lens the student will see them bigger than with the low-power lens. However, the field of view (the visible area through a lens) is reduced when a higher power lens is used, so fewer pollen grains will be seen.
The answer therefore is the option of higher number of pollen grains of small size for the low-power lens, and lower number of pollen grains of larger size for the high-power lens.
Answer:
Option (1) Elastomers must be amorphous, having chains that are extensively coiled and kinked in the unstressed state and (2) there must be some crosslinking.
Explanation:
An elastomer may be defined as a type of polymer that includes both the properties of viscosity and elasticity. The intermolecular forces present between the elastomers are weak.
The elastomers should be amorphous solid. Their chains are kinked and extensively coiled in the non stressed state. The elastomers must include the cross linking in its structure.
It is called genetic engineering
The correct answer is B. Secondary succession
Explanation:
In ecosystems, secondary succession occurs as certain events such as fires cause vegetation to temporarily disappear from one area. However, as soil is not affected negatively, vegetation grows again after some time, which means there is a secondary growth of vegetation and changes in the structure of an ecological community.
This term applies to the situation in the 1988 fires in Yellowstone Park because the fire destroyed the vegetation in the zone temporarily, but as the soil was intact after years or decades the vegetation will grow again, although this might implied changes in the ecosystem.
In my opinion, out of the many indexes about the development of a country, the three most reliable ones about the level of development would be the GDP nominal, the GDP per capita, and the human rights index.
The GDP nominal will show the overall welfare of the country, the sum of its economy, its production, the way it manages the finances, the progress or decline it is making.
The GDP per capita will show us the average income of the people in the country. So this index will provide us with information about how well the wealth in the country is distributed, are the people poor, middle class, or rich, and what they can or can not afford in their lives.
The human rights index is very important as it defines the basics of the daily lives and the rights that the people have. The more freedom the people have in their expression, the choices in life, their actions, the happier the people would be, and vice versa, the more restricted they are, the less happy would they be.
