When do scientists consider a hypothesis valid? a. when the hypothesis is testable b. when the hypothesis is published in a scientific journal c. when more than one person supports the hypothesis d. when experimentation shows it to be true

enhanced global partnerships and exploration capabilities may advance international preparedness for protecting the earth from catastrophic events such as some asteroid strikes, advancing collaborative research on space weather and protecting spacecraft by developing new means for space debris removal.

a- multicellular

b-eukaryotic

c-no cell wall

d-heterotrophic

e-autotrophic