What is the missing word? stem cells have not yet so they retain the ability to develop into other types of cells.

Why are current extinctions of concern to enviromentalists?

When does a spring tide occur? question 9 options: they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur twice a year in the spring and fall. they occur on the date of the vernal equinox each year, no matter what stage the moon is in. this is why they are called spring tides. they occur when the sun, moon, and earth are at 45-degree angles from each other. this happens once every spring. they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur all year long.

We all have different forms of genes from our parent(s).what are these different forms called? a.alleles b.characters c.dna d.resources