Answer:
Explanation:
This is because ferns are vascular plants i.e they have vascular tissues which are xylem and phloems which help to conduct water and nutrients while mosses are non vascular plants.
2. Ferns sporophytes are differentiated into true leaves, stems and true roots while mosses lack true roots, stems and leaves.
Underground stems are modified part of plants that are derived from stem tissues which grow under the ground. Underground stems grow beneath the soil. Examples include Rhizomes, ginger, tubers e t.c.
Answer: False
Explanation:
Pathogens can be transmitted in many ways. It can spread by direct contact, indirect contact, or by vectors.
The mode of transmission can be skin contact, airborne particles, touching a surface, bodily fluids, touched by an infected person.
The mode of transmission can be vector that carries disease and helps in disease transmission.
So, the pathogens can be transmitted by direct contact, indirect contact or by vectors and by many more ways.
Answer:
False .
atmosphere in early earth was filled with both methane and ammonia
Now days we have nitrogen, oxygen Carbon dioxide and variable gases
Improving energy efficiency of a home generally means reducing the exchange of outdoor air (ventilation) with indoor air that can be contaminated with radon gas.
Explanation:
The presence of radon gas is not detectable by humans. It is odorless, colorless, tasteless, and radioactive. It can cause lung cancer over time and quantity breathed in. It enters buildings through cracks and voids in their foundations from the soil surrounding them.
The energy efficiency of buildings has been steadily increasing as we try to conserve energy and reduce costs. By so doing we also reduce the airflow between inside and outside, especially during the colder months of the year.
This practice will result in radon gas concentration buildup to values that could become unsafe for human consumption.
There are a number of methods to reduce the threat of radon gas in a house, but first there needs to be a measurement of the level of gas in the building. If the threat is high, the radon gas must be removed.
