D. A struggle for existence is apparent.
If a struggle for existence is apparent, natural selection occurs because all of the weak/unfit/unadapted ones die.
Answer:
lungs:
The blood first enters the right atrium.
The blood then flows through the tricuspid valve into the right ventricle.
When the heart beats, the ventricle pushes blood through the pulmonic valve into the pulmonary artery.
The pulmonary artery carries blood to the lungs where it “picks up” oxygen.
It then leaves the lungs to return to the heart through the pulmonary vein.
The blood enters the left atrium.
It drops through the mitral valve into the left ventricle.
The left ventricle then pumps blood through the aortic valve and into the aorta. The aorta is the artery that feeds the rest of the body through a system of blood vessels.
Blood returns to the heart from the body via two large blood vessels called the superior vena cava and the inferior vena cava. This blood carries little oxygen, as it is returning from the body where oxygen was used.
The vena cavas pump blood into the right atrium and the cycle begins all over again.
Answer:carbon dioxide
Explanation:
Cause animals release carbon dioxide for plants to inhale amd exhale oxygen
Answer:
Parasitism
Explanation:
This is because parasitism is a type of relationship that exist between organisms where one which is the predator feed on the prey thereby causing harm or injury or death to the prey. In the question, small frogs are the predators and insects are the prey, therefore the predators cause harm to the prey, meaning they only benefits from the farm they cause the prey.
