Avery long time, sometimes hundreds of years, to change a species
a) evolution
b) photosynthesis

What do you need to use in order to work as an environmental scientist? you need to use the scientific method and__ in order to work as an environmental scientist.

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

How secretion and excretion both are different? explain in simple language.