How many contrasting characteristics did each trait have?

alot

Explanation:

Seven pairs of contrasting characters in pea plants were studied by Mendel in his experiments. They were : i) form of seed; ii) colour of cotyledons; iii) colour of seed coat; iv) form of pod; v) colour of pod; vi) position of flower; vii) height of plant (length of stem).

Explanation:

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.