Answer:
2. It is made of sandstone which is very porous and is easily penetrated by rainwater
Explanation:
The White House is made of gray-colored sandstone that is brought from quarry in Aquia, Virginia. The north and south porticos of white house building are constructed with red Seneca sandstone brought from Maryland. These sandstones are porous in which rainwater is easily penetrated in it that cause damage to the white house building so it is concluded that the building is made of porous sandstone.
The given is incomplete as the options are missing. The correct options for the given question are as follows-
(A) cultivation of agricultural land inhibits the decomposition of organic matter
(B) nitrogen-fixing bacteria are not as plentiful in agricultural soils because of the use of pesticides
(C) land that is available for agriculture tends to be nutrient-poor
(D) the nutrients that become the biomass of plants are not cycled back to the soil on lands where they are harvested
Answer:
Option (D)
Explanation:
In order to carry out agricultural practices, the soil must be rich in essential nutrients for the growth of crops. The soil fertility is a key role in the production of crops.
This agricultural land often requires a large amount of these nutrients and minerals because some of the nutrient minerals are converted into plant biomass which is then used up to produce energy in other sectors. So, the nutrients that were present in the soil are taken away and not transferred back into the soil. This means that the nutrient cycle gets affected. Due to this reason, there requires a constant supply of nutrients into the agricultural fields.
Thus, the correct answer is option (D).
Answer:
Polysaccharides are the genetic material.
Explanation:
Avery did not observe transformation using the extracts containing degraded DNA. On the other hand, extracts with degraded RNA, proteins, and polysaccharides exhibited transformation. Therefore, he concluded that DNA is the genetic material responsible for transformation. If he would have observed the process of transformation using extracts containing degraded DNA but not with degraded polysaccharides, he might have concluded that "polysaccharides were the genetic material responsible for the process of transformation."
The last three are correct
A dam is a structure built across a stream or river to hold water back. Dams can be used to store water, control flooding, and generate electricity.