How do we sometimes benefit from introduced species that are not invasive

Which of the following is a period in the paleozoic era? devonian cambrian permian all of the above

What do transitional fossils best support?

Once an egg cell is fertilized by sperm, the cell then, as the embryo develops, it receives nourishment and eliminates wastes by transferring substances from its blood to its mother's blood. a. becomes a fetus immediately and exits the womb b. begins to divide and implants itself in the wall of the uterus c. remains in the uterus without dividing for several months d. travels back to the ovaries until the fetus is developed