In an eight-cell embryo of an organism, the cells of the upper tier are aligned over the cells of the lower tier at a slight angle. which organism is it likely to be?

earthworm

starfish

sea cucumber

Which macromolecules are polymers made of nucleotides (a) fatty acids (b) nucleic acids (c) carboxylic acids (d) amino acides

Which of the following represents a negatively charged ion? of t 7

How do you know that the plant cells in these two images have different jobs, or functions? a. because all plant cells serve different functions b. because they are two different colors c. because their dna are different d. because their structures are different