In an E. coli conjugation experiment, the donor cell is foun…

In an E. coli conjugation experiment, the donor cell is found to be thr+, leu+, his+, and the F- cell is thr-, leu-, and his-. When the mating is interrupted after 10 minutes and the recipients are plated, they are found to be leu+ and his+ but thr-. What can you conclude?

Two boxes move at a right angle to each other on a frictionl…

Two boxes move at a right angle to each other on a frictionless surface, as shown in the figure below. The mass moving along the x-axis has a mass of 6.0 kg and a speed of 10 m/s. The mass moving along the y-axis has a mass of 4.0 kg and a speed of 20 m/s.  The directions of the two velocity vectors are indicated in the figure. The boxes collide and stick together after the collision. What is their common speed after the collision?