Answer: a). AA
Explanation: Every trait is controlled by at least a pair of gene. Genes have different forms known as alleles. Alleles can be dominant or recessive. A dominant allele expresses itself in the presence of a recessive allele and masks the effect of a recessive allele. A recessive allele cannot express itself in the presence of a dominant allele and it's effect is masked by a dominant allele. Dominant alleles are usually written in upper cases such as A, T, while recessive alleles are usually written in lower cases such as a, t. The two alleles that determines a trait is called a genotype. A genotype can be homozygous if the two alleles are identical such as in AA or aa
and can be heterozygous if the two alleles are not identical such as in Aa, Tt.
Parasites need a host. If a host tries to get rid of the parasite or kill it, then the parasite either has to leave the body or die.
Sponges have specialized cells and an endoskeleton, but they lack tissues and body symmetry. ... They include jellyfish and corals, both of which have radial symmetry. All cnidarians have nematocysts, and many are bioluminescent. They may exist in medusa and/or polyp form.
Answer:
Option C
Explanation:
Miller and Urey performed an experiment, using some inorganic molecules such as water, methane, carbon dioxide and hydrogen in laboratories conditions similar to early earth conditions .
Amino acids molecules formed as the result of this experiment, this proved that small organic molecules such as amino acids are formed from inorganic molecules.
Hence, the correct answer is option C
