Which of the following led thomas hunt morgan to conclude that crossing over occurs?

a. dominant linked genes often express codominance.

b. genes on the same chromosome are sometimes inherited separately.

c. genes on the same chromosome are linked and inherited together.

d. all of the above are correct.

When does a spring tide occur? question 9 options: they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur twice a year in the spring and fall. they occur on the date of the vernal equinox each year, no matter what stage the moon is in. this is why they are called spring tides. they occur when the sun, moon, and earth are at 45-degree angles from each other. this happens once every spring. they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur all year long.