C. Increased availability of food production
Answer: (A) The conclusion is valid because the independent and dependent variables in experiment were controlled.
Explanation: There are some basics requirements in order for an experiment to be valid: hypothesis, monitoring, independent and dependent variables and constants.
Answer:D
Explanation: The pulmonary air sacs of birds only permit a unidirectional flow of air through the lungs. Unidirectional flow means that air is inhale and exhale through one trachea alternatively. This means the bird lungs only receive largely fresh air which has a high oxygen content during inhalation and do not receive fresh during exhalation. While air flow bidirectional in mammals.
The F1 offspring of Mendel's classic pea plant crosses always looked like one of the two parental varieties because he crossed a homozygous dominant plant with a homozygous recessive plant so each plant received one recessive allele and one dominant allele. All of the plants looked like one plant because the dominant allele overshadowed the recessive allele
Blood type O can be given to anyone.
