A.
Explanation:
Pioneer plants are to plants species that appear first in virgin land – such an after a volcanic eruption. They are mainly lower plants such as lichen, fungi, and noses. These species can grow on rocks and break them down over time to form soil. This is due to the fact that the plants have very shallow roots that can even grow in the small crevices of rocks and can draw water from the atmosphere – moisture. This releases the nutrients in the rocks and makes them available to higher plants that have deeper roots. The ecology of the region will ultimately be succeeded by a climax community over time, mainly dominated by tree species.
elements have equal number of protons and neutrons
the condensed format is when the closest noble gas with the closest electron configuration is given, this closest noble gas atomic number should be lesser than the atoms atomic number
atomic number of Kr is 36
1 electron in 5s subshell and 7 electrons in 4d subshell.
there's a total of 36 + 1 + 7 = 44 electrons
atomic number of the atom is 44
element with atomic number 44 is Ruthenium - Ru
answer is Ru
Answer:
To monitor Pressure increase
Explanation:
the more pressure, the higher the production of the gas, which can be recorded, more pressure meaning higher production. Then vary the temperature.
Answer:
Period
Explanation:
horizontal is a period and verticle is a group
Answer : The value of diffusion coefficient is, 
Explanation :
Formula used :

where,
D = diffusion coefficient = ?
= 
= 
R = gas constant = 8.314 J/mol.K
T = temperature = 
Now put all the given values in the above formula, we get:


Thus, the value of diffusion coefficient is, 