They are ectotherms.
hope it is helpful to you
I'm not 100% sure, but I'd say the availability of vaccines and medicine.
Double fertilization-plants with seeds (flowering plants), two male gametes joining with female gametophyte
Gametophyte generation-both (haploid, sexual stage stage-gametophyte, and the diploid stage that produces spores – sporophyte)
Endosperm formed-plants with seed because it is a tissue formed inside the seed which surrounds the embryo and provides nutrition
Mitosis-both (mitosis occurres in spores)
Spores develop into gametophytes-both but, in seedless plants sporophyte produces spores that will develop into a new organism (multicellular gametophyte) using mitosis, while spores of seed plants are produced internally and develop into more complex structures.
D. an arctic fox is brown in summer and white in winter