Answer: Options A, B, C, D at correct
Explanation:
Cnidarians are a branch of invertebrates characterised by by a radially symmetric body including a saclike internal cavity and nematocysts; stinging structures that aids in feeding. They are also known as coelentrates. They are diploblastic (2 body layer). They also reproduce asexually by various mean including budding. Example include sea anemones, hydra, corals, jellyfish etc
The right answer is D (less responsive to antigens)
It is proven that, after puberty, thymus activity (an organ that is included in the lymphatic system, producing T cells that pick up antigens) decreases and that in adult and aged people the thymus has no role. Work done in humans indicate that in fact the cellularity begins to decline from birth in favor of lymphocyte perivascular spaces and connective and adipose tissue, which leads to a decrease in the capture of antigens.
Answer:
False
Explanation:
In osmosis, water always moves from an area of higher water concentration to one of lower concentration.
Answer:
<em>The correct option is B) as the light colored moths were seen and eaten, the allele for dark colour became more prevalent in the population.</em>
Explanation:
The process of natural selection tends to favour those organisms which are better adapted to live in an environment. Evolution changes the allele frequencies of a population over time depending on the traits favoured by natural selection.
Before the industrial revolution, the colour of the trees was lighter and hence, the light coloured moths were better adapted to such environments as they could hide from predation. After the industrial revolution, the colour of the woods of trees became darker. The light coloured moths were no more able to hide from their predators and hence their population declined.
