What do all elements in a column in the periodic table have in common?
their atoms have the same number of valence electrons.
their atoms have the same atomic mass.
their atoms have the same number of protons and electrons.
their atoms have the same number of neutrons.

Option A

Explanation:

The elements are arranged in a periodic table based on their properties. The group of similar elements share common characteristics and hence kept in the same periods.

The elements having same number of valence electrons in their outer shell. As they have same number of valence electrons they have similar properties in terms of reactivity, stability, et cetera.

Hence, the correct answers is option A

sand 60

clay 10

silt 30

sandy loam should be dominated by the sand. as the amount of sand increased, the amount of slit needed to anchor the plants' roots to the sand will also be increased. even though the amount is very little, 10% part of clay is still necessary for proper oxidation.

answer: a) a compound microscope has a greater magnification ability than a simple microscope.

explanation: