Cephlochordates have a backbone that extends from their tail to where? their gills their anus their heart their head

Astudent observes a star from two positions of earth in its orbit, in summer and winter, and measures the change in the position of the star. which of these can be best calculated by this method?

What abo controlling alleles could kim give her child

When listening the levels of orginization in orginisims from the smallest to most complex , which level is just below organs in complexity