Answer: 2, 4 and 5.
Explanation:
Human system are made of various organs which in turn are made up of various tissues which in turn are made up of various cells. Cells are therefore much more numerous than systems.
As already mentioned, organs are made up of tissues which are made up of cells so statement 4 is right.
As systems are made up of various organs working together, they are more complex than the individual organs. For instance, the Muscular system is more complex than the triceps or bicep muscles.
Answer:
The correct answer is option A. "directional selection".
Explanation:
Directional selection is a type of natural selection at which traits with extreme characteristics are selected over traits with medium characteristics. In this case, a long-term climatic change resulted in all seeds that are the fountain of food for finch becoming hard. This will result in a directional selection on bill size in the finch population, where large-billed birds will be selected over small and medium-billed birds.
Answer:
The beating or fanning movements of three pairs of maxilliped flagella in crabs and crayfish modify exhalent gill currents while drawing water over chemoreceptors on the head. They play an integral part both in signalling by distributing urine odours, and in active chemosensation.
Explanation:
Answer:
1. physical and chemical barriers
2.non-specific innate response
3. specific adaptive responses
Explanation:
