Frogs Anatomy Circulatory System

Compared to those of humans, the erythrocytes in frogs are:

1. Without nucleus but with haemoglobin

2. Nucleated and with haemoglobin

3. Very much smaller and fewer

4. Nucleated and without haemoglobin

What is the name of the blood vessel that carries deoxygenated blood from the body to the heart in a frog?
1. Pulmonary vein
2. Vena cava
3. Aorta
4. Pulmonary artery