In a population that is not evolving, which of the following can cause a change in allele frequencies in a specific direction?

In which of the following conditions does the gene frequency remain constant in a population?

In a random mating population,the frequency of the dominant allele is $0.7$. What will be the frequency of the recessive phenotype?

If the measured allele frequency differs from the expected value,what does it indicate?

There are two alleles ($A_1$ and $A_2$) in a population. If the frequency of one allele $(A_1)$ is $0$,then the frequency of the other allele $(A_2)$ is .....

In a population of $10,000$ sheep,$4900$ have a homozygous dominant genotype $(AA)$ and $4200$ are heterozygous $(Aa)$ sheep. The remaining sheep have a homozygous recessive genotype $(aa)$. Find the frequency of the homozygous dominant allele $(p)$ as per the Hardy-Weinberg principle.