It acts as a reactant in a chemical reaction.
1) B
(I'm not so sure of this one) All of the other options have a steady impact on population regardless of the density of organisms except competition
2) D
Increased carbon dioxide levels would not hinder plant growth, and tsunamis aren't really linked to carbon dioxide levels. Increased carbon dioxide is unlikely to lower the air temperature so only D is left.
3) A
4) Three properties of water that allow it to sustain life are that it is adhesive, it is a good solvent, and cohesion. Adhesion is important in situations such as water travelling up xylem tubes in plants so that the water is not pulled down by gravity and can reach parts of the plant that need water. Cohesion allows the water being pulled up the xylem to stay together and for water molecules to be pulled when a neighbouring one is moved. Water being a good solvent allows inorganic minerals to be taken with water through vascular tissue, such as in the previous example.
Answer:
D and B
Explanation:
it is hard to explain but
Xylem is responsible for the transport of water and dissolved ions
The phloem is made of companion cells that form to connect pipes
The question is incomplete as it does not have the options-
A) Gamma-aminobutyric acid (GABA)
B) Acetylcholine
C) Dopamine
D) Serotonin
Answer:
The correct answer will be option- Dopamine
Explanation:
Parkinson's disease is one of the movement disorders which gets worse with time. The disease is caused due to the degeneration of the neurons in the brain which are responsible for the body movement.
Although many brain areas are affected the most common result is due to the loss of neurons in the substantia nigra in which the neurons produce a neurotransmitter called dopamine which is responsible for the body movements.
Thus, Dopamine is the correct answer.
