Biology Answers

The embryo of chick is developed Inside the extra embryonic cavity made by

if the perpendicular distance between the man's quadriceps tendon and his knee joint center of rotation remained the same (5cm), how much force would his quadriceps muscle have had to produce at this point?"

When the man's knees were at a 40 degree angle the center of mass of the man and the box was 26cm behind the knee joint center of rotation. How much torque (Nm) did this this place on his knee joint?

20) A man extends his knees as he lifts a box. When his knees reach a 80 degree angle, the center of mass of the man and the box is 20cm behind the center of rotation of his knee joint. The weight of the man (minus his lower legs and feet) is 160 pounds and the weight of the box is 40 pounds. How much torque would the mans left quadriceps muscle have to produce to maintain this position? (Hint: The man is standing on both legs. Would his left leg have to support the entire weight?)"

Analyze It
Tom and Alice are the parents of four children. Tom has earlobes that are not attached to the side of his head, which is a dominant trait. Alice has earlobes that are attached, which is a recessive trait. Use the two Punnett squares ("E" represents the dominant earlobe gene, and "e" represents the recessive earlobe gene) to answer the following questions.

What must be true about the earlobes of Tom's parents?

What must be true about the earlobes of Alice's parents?

Which Punnett square allows for the possibility that Tom and Alice's children have attached earlobes?

what is the anatomy of the heart?

Why is it so important for cells to divide?

The larvae form of this mosquito lives exclusively in old tires, and old tires are identical across all habitats. If water dries before larvae transition to adulthood, they die. Rain (which fills the tires with water) is more frequent in Florida than in Southern Maine. How do you expect mosquitoes to differ in respect to variation in size and age at metamorphosis?

For a trait like body size, why is plasticity adaptive? Why do alleles that allow for plasticity increase in populations via natural selection? Can I get an example?