Using the information found below, which shared characteristics are found for points B, C and D? (A is filled in for you already).
1: B mammary glands, C placenta, D two pairs of limbs
2: B placenta, C mammary glands, D two pairs of limbs
3: B two pairs of limbs, C mammary glands, D placenta
4: B two pairs of limbs, C placenta, D mammary glands
