Answer:
The correct option is <em>B. Crossing- over </em>
Explanation:
In biology, crossing over can be described as a phenomenon by which homologous chromosomes exchange segments during the process of meiosis.
The unexpected results came because the DNA segment between the homologous chromosomes was exchanged during meiosis. The alleles got shuffled by this process and hence showed the unexpected results.
Crossing over and independent assortment are phenomenon which occurs only during the process of meiosis. These phenomenons cannot be observed during mitosis.
<span>Answer: Cellular differentiation is responsible for one daughter cell becoming a sieve tube whereas the other becomes a companion cell. Cell differentiation occurs as different genes are switched on and off.
Hope this answer helps!</span>
Answer: This is a positive feedback loop.
Explanation:
The protein digestion in the body is an example of the positive feedback. The gastric secretions is stimulated chiefly by the action of three chemicals.
These chemicals are acetylcholine, histamin and gastrin. These chemicals stimulate the parietal cells to secrete HCL and intrinsic factors.
The chief cells secrete pepsinogen in response to the gastrin and ACh. As the dietary proteins are digested, it breaks down the amino acids and peptides.
This stimulates the G cells of the stomach to secrete more gastrin. This is how the positive feedback loop for the protein digestion works.
Answer:
1. growth
2.causes biochemical reactions
3. acts as a chemical messenger that aids communication between your cells, tissues and organs.
4. provides structure
5.maintains proper pH
6. balances fluids in the body.
7.boosts immune health
8. transports and stores nutrients
9. provides energy for you body
Explanation:
