Question

traits studied by mendel
plant height tall short
flower color purple white
flower position end of stem middle of stem
pod color green yellow
pod shape inflated constricted
seed color yellow green
seed shape smooth wrinkled
what do these characteristics all have in common?
they are all dominant.
they can all be easily observed.
they are all recessive.
they can all be applied to other plants.

Explanation:

Mendel's studied traits like plant - height, flower - color etc. are all visible and can be easily noticed without the need for complex equipment or procedures. They are not all dominant or all recessive, and not all applicable to other plants in the same way.

Answer:

They can all be easily observed.