The correct option is B.
A multi cellular organisms has many cells which carry out various function and which are organised into tissues, organs and organ system. A unicellular organism on the other hand has only one cell with different cell organelles. Thus, in unicellular organisms, it is the cell organelles that carry out different functions. <span />
A pollen grain from on
e flower fertilizes another flower, resulting in the development of a seed.
A frog releases sperm over eggs that were laid by another frog, and these cells fuse together.
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Answer:
Villi, alveoli and nephrons are similar as :-
B. They provide large surface areas for molecular exchange.
Answer:
Non-coding DNA regions play important roles in regulating transcriptional activity by encoding different types of non-coding RNAs (ncRNAs), acting as scaffold attachment regions, acting as enhancer specific regions, etc.
Explanation:
Historically, it had been believed that non-coding DNA sequences were 'junk DNA' since they don't encode for proteins (beyond the sequences that are transcribed into functional non-coding RNAs, i.e., transfer RNA and ribosomal RNA). However, in the last years, it has been shown that non-coding DNA sequences play critical roles in regulating gene expression and genome function. For example, evolutionary conserved non-coding RNAs (ncRNAs) with regulatory roles on gene expression such as, for example, long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been mapped in non-coding DNA sequences, thereby evidencing the functional significance of these regions. In consequence, the conservative nature of certain non-coding DNA sequences evidence that mutations in such regions may have significant deleterious effects, and thereby they could have a negative impact on the fitness of the individual.
