in the article, which technologies have been developed to enhance space exploration? choose all that apply

Each pair of clay balls represents two planetesimals. if each planetesimal is composed of the same material and is separated he the same distance, which pair experiences the frayed gravitational attraction?

If a cell is placed into a hypertonic environment,what will happen to it ? a)it will shrink or shrivel b)nothing c)it will burst d) it will expand or enlarge

Why are current extinctions of concern to enviromentalists?