12. An atom with an atomic number of 34, and a mass number of 79 has: protons
neutrons
electrons
b. 45 Protons, 45 Neutrons, 34 Electrons
a. 34 Protons, 45 Neutrons, 34 Electrons
c. 45 Protons, 34 Neutrons, 34 Electrons

Answer is A.

Explanation:

atomic number is number of protons.

atomic mass is protons + neutrons

and electrons = number of protons

Answer;

The continents were once connected, and marsupials were able to migrate over the land.

Explanation;

-Marsupials are the group of mammals commonly thought of as pouched mammals. They give live birth, but they do not have long gestation times like placental mammals. Instead, they give birth very early and the young animal, essentially a helpless embryo, climbs from the mother's birth canal to the nipples.

-The first mammals with the marsupial's distinctive mode of reproduction arose on the ancient southern super-continent of Gondwanaland. Later, after this great land mass broke up into separate continents, the ancestors of marsupials were separated from other mammals and evolved in isolation on the new continents of Australia and South America.