40 pts plz help
1
Part A: design a food chain with four trophic levels, and identify the organism in each level.
Part B: Can humans ever occupy the lowest, or first, trophic level?

2
One example of ecological interaction in the ocean is the relationship between boxer crabs and sea anemones. In this unique relationship, the crabs "wear" the stinging anemones on their claws as an extra level of protection from predators. The anemones are then free to eat any leftovers from the crab's meal.

Part A: Identify which type of symbiotic relationship the above example is. (1 point)

Part B: In a parasitic type symbiotic relationship, one species of the pair is harmed. Make a fictional change to one of the members of the boxer crab/sea anemone relationship so that it becomes a parasitic relationship. Describe what that change is. (3 points)

What is a dendrite and what does it do?

If a human has 23 pairs of chromosomes in every muscle cell of its body how many chromosomes will be in a human egg or sperm

Choose the incorrect statement (a) the motor end plate membrane is only capable of generating graded potentials, but it is contiguous with the skeletal muscle sarcolemma, which can generate action potentials. (b) propagation of an action potential through the t-tubules into the sarcoplasmic reticulum triggers the release of ca++ into the cytoplasm of a skeletal muscle fiber. (c) the generation of suprathreshold endplate potentials in multiple muscle fibers could be due to the increased frequency of action potential generation at the axon hillock of a single motor neuron. (d) a greater amount of ach would be found in the presynaptic vesicles of a motor unit that fired several action potentials after exposure to botulinum toxin, than in a motor unit that fired several action potentials after exposure to the venom of the krait snake (which contains α-bungarotoxin).