Imagine the autosomal dominant cb allele produces black coat color in dogs, and the recessive cw allele produces a white coat color. the cb allele is also recessive for lethality; pups with the cbcb genotype die well before birth, and their remains are resorbed by the mother’s uterus. imagine you cross heterozygous black male dog with a heterozygous black female. what ratio of genotypes and phenotypes do you expect to see in the f1 offspring? if more than one genotype produces the same phenotype, list all the genotype/phenotype combinations separately.

the ratio of genotypes will be 2:1 (CBCw:CwCw) and the phenotype ratio will be 1:1 (black dog:white dog)

Explanation:

If heterozygous black male dog is crossed with a heterozygous black female then:

P: CBCw  x  CBCw

F1: CBCB  CBCw CBCw CwCw

Since CBCB genotype will die before birth, the ratio of genotypes will be 2:1 (CBCw:CwCw) and the phenotype ratio will be 1:1 (black dog:white dog).

CBCw genotype, which is heterozygous will produce black phenotype, since the allele CB is dominant over Cw allele.

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.