Number of offspring produced over a period of time

One tradeoff is between number of offspring produced and the amount of energy (both physical resources and parental care) put into each offspring.

they absorb it i think

not sure

you

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands