Adna molecule consists of two polynucleotide strands that form a double helix. the strands are held together by hydrogen bonds between the nitrogen‑containing bases. one strand is complementary to the other strand, which means that a base on one strand is paired with a base on the opposite strand. the nucleotide bases in dna are adenine (a), cytosine (c), guanine (g), and thymine (t). choose the dna sequence complementary to gact (a) agtc (b) gact (c) tcag(d) ctga

D) CTGA

Explanation:

As the question says, DNA consists of two complementary strands held together by hydrogen bonds between bases.

Nucleotides are the monomers of DNA, which means they are the basic building block of it. The nucleotides consists of:

Adenine pairs with Thymine, they form two hydrogen bonds between them. While Cytosine pairs with Guanine, they form three hydrogen bonds between them. This is because each base can bond with a specific base in a process called complementary base pairing.

So, the complementary sequence of GACT is CTGA.

organisms that lack symmetry are called asymmetrical and belong to phylum porifera/sponges.

organisms with specialized stinging cells belong to phylum cnidaria. stinging cells are called cnidoblast cells.

cnidarians show two morphological forms : polyp (sessile) and medusa (mobile)

filter feeding is observed in porifera members.  

alternation of generation is observed in coelenterata or cnidaria. there is alternation of asexual polyp form and sexual medusoid form. it is also referred as metagenesis.