Answer:
DNA binding domain and allosteric domain
Explanation:
Repressors are proteins that inhibit gene expression, They usually have DNA or RNA binding site which enables them to binde to the operator or associated silencers. Allosteric domain is the site for the binding of other molecules, such as corepressors and inducers that regulate repressor's activity.
4) digestive and circulatory, because the bladder is part of the digestive system. The circulatory system carries blood around the body using blood vessels.
The correct answer is option B. The scientists were studying if the mud snails can reproduce both sexually and asexually. The characteristics in the study included parameters such as the mating season, number of offspring, effect of environmental stress conditions and lack of mates. Out of all the parameters being studied can affect asexual reproduction in the mud snail but lack or presence of mates is a parameter required to be studied to determine the mode of reproduction i.e. sexual or asexual because need for mates or mate dependent reproduction occurs in case of sexual reproduction.